programming.po

# SOME DESCRIPTIVE TITLE.
# Copyright (C) 2001-2025, Python Software Foundation
# This file is distributed under the same license as the Python package.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
# Translators:
# Stefan Ocetkiewicz <stefan.ocetkiewicz@gmail.com>, 2022
# Krzysztof Abramowicz, 2022
# Maciej Olko <maciej.olko@gmail.com>, 2022
# Rafael Fontenelle <rffontenelle@gmail.com>, 2024
# Stan Ulbrych, 2025
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: Python 3.13\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2025-04-11 14:19+0000\n"
"PO-Revision-Date: 2021-06-28 00:52+0000\n"
"Last-Translator: Stan Ulbrych, 2025\n"
"Language-Team: Polish (https://app.transifex.com/python-doc/teams/5390/pl/)\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Language: pl\n"
"Plural-Forms: nplurals=4; plural=(n==1 ? 0 : (n%10>=2 && n%10<=4) && "
"(n%100<12 || n%100>14) ? 1 : n!=1 && (n%10>=0 && n%10<=1) || (n%10>=5 && "
"n%10<=9) || (n%100>=12 && n%100<=14) ? 2 : 3);\n"

msgid "Programming FAQ"
msgstr "FAQ - programowanie"

msgid "Contents"
msgstr "Zawartość"

msgid "General Questions"
msgstr "Pytania ogólne"

msgid ""
"Is there a source code level debugger with breakpoints, single-stepping, "
"etc.?"
msgstr ""
"Czy istnieje debugger kodu źródłowego z obsługą punktów przerwania, krokowym "
"wykonywaniem akcji itp.?"

msgid "Yes."
msgstr "Tak"

msgid ""
"Several debuggers for Python are described below, and the built-in function :"
"func:`breakpoint` allows you to drop into any of them."
msgstr ""

msgid ""
"The pdb module is a simple but adequate console-mode debugger for Python. It "
"is part of the standard Python library, and is :mod:`documented in the "
"Library Reference Manual <pdb>`. You can also write your own debugger by "
"using the code for pdb as an example."
msgstr ""

msgid ""
"The IDLE interactive development environment, which is part of the standard "
"Python distribution (normally available as `Tools/scripts/idle3 <https://"
"github.com/python/cpython/blob/main/Tools/scripts/idle3>`_), includes a "
"graphical debugger."
msgstr ""

msgid ""
"PythonWin is a Python IDE that includes a GUI debugger based on pdb.  The "
"PythonWin debugger colors breakpoints and has quite a few cool features such "
"as debugging non-PythonWin programs.  PythonWin is available as part of "
"`pywin32 <https://github.com/mhammond/pywin32>`_ project and as a part of "
"the `ActivePython <https://www.activestate.com/products/python/>`_ "
"distribution."
msgstr ""

msgid ""
"`Eric <https://eric-ide.python-projects.org/>`_ is an IDE built on PyQt and "
"the Scintilla editing component."
msgstr ""

msgid ""
"`trepan3k <https://github.com/rocky/python3-trepan/>`_ is a gdb-like "
"debugger."
msgstr ""

msgid ""
"`Visual Studio Code <https://code.visualstudio.com/>`_ is an IDE with "
"debugging tools that integrates with version-control software."
msgstr ""

msgid ""
"There are a number of commercial Python IDEs that include graphical "
"debuggers. They include:"
msgstr ""

msgid "`Wing IDE <https://wingware.com/>`_"
msgstr ""

msgid "`Komodo IDE <https://www.activestate.com/products/komodo-ide/>`_"
msgstr "`Komodo IDE <https://www.activestate.com/products/komodo-ide/>`_"

msgid "`PyCharm <https://www.jetbrains.com/pycharm/>`_"
msgstr "`PyCharm <https://www.jetbrains.com/pycharm/>`_"

msgid "Are there tools to help find bugs or perform static analysis?"
msgstr ""

msgid ""
"`Pylint <https://pylint.pycqa.org/en/latest/index.html>`_ and `Pyflakes "
"<https://github.com/PyCQA/pyflakes>`_ do basic checking that will help you "
"catch bugs sooner."
msgstr ""

msgid ""
"Static type checkers such as `Mypy <https://mypy-lang.org/>`_, `Pyre "
"<https://pyre-check.org/>`_, and `Pytype <https://github.com/google/"
"pytype>`_ can check type hints in Python source code."
msgstr ""

msgid "How can I create a stand-alone binary from a Python script?"
msgstr ""

msgid ""
"You don't need the ability to compile Python to C code if all you want is a "
"stand-alone program that users can download and run without having to "
"install the Python distribution first.  There are a number of tools that "
"determine the set of modules required by a program and bind these modules "
"together with a Python binary to produce a single executable."
msgstr ""

msgid ""
"One is to use the freeze tool, which is included in the Python source tree "
"as `Tools/freeze <https://github.com/python/cpython/tree/main/Tools/"
"freeze>`_. It converts Python byte code to C arrays; with a C compiler you "
"can embed all your modules into a new program, which is then linked with the "
"standard Python modules."
msgstr ""

msgid ""
"It works by scanning your source recursively for import statements (in both "
"forms) and looking for the modules in the standard Python path as well as in "
"the source directory (for built-in modules).  It then turns the bytecode for "
"modules written in Python into C code (array initializers that can be turned "
"into code objects using the marshal module) and creates a custom-made config "
"file that only contains those built-in modules which are actually used in "
"the program.  It then compiles the generated C code and links it with the "
"rest of the Python interpreter to form a self-contained binary which acts "
"exactly like your script."
msgstr ""

msgid ""
"The following packages can help with the creation of console and GUI "
"executables:"
msgstr ""

msgid "`Nuitka <https://nuitka.net/>`_ (Cross-platform)"
msgstr ""

msgid "`PyInstaller <https://pyinstaller.org/>`_ (Cross-platform)"
msgstr ""

msgid ""
"`PyOxidizer <https://pyoxidizer.readthedocs.io/en/stable/>`_ (Cross-platform)"
msgstr ""

msgid ""
"`cx_Freeze <https://marcelotduarte.github.io/cx_Freeze/>`_ (Cross-platform)"
msgstr ""

msgid "`py2app <https://github.com/ronaldoussoren/py2app>`_ (macOS only)"
msgstr ""

msgid "`py2exe <https://www.py2exe.org/>`_ (Windows only)"
msgstr ""

msgid "Are there coding standards or a style guide for Python programs?"
msgstr ""

msgid ""
"Yes.  The coding style required for standard library modules is documented "
"as :pep:`8`."
msgstr ""

msgid "Core Language"
msgstr "Rdzeń języka"

msgid "Why am I getting an UnboundLocalError when the variable has a value?"
msgstr ""

msgid ""
"It can be a surprise to get the :exc:`UnboundLocalError` in previously "
"working code when it is modified by adding an assignment statement somewhere "
"in the body of a function."
msgstr ""

msgid "This code:"
msgstr "Ten kod:"

msgid "works, but this code:"
msgstr "działa, ale ten kod:"

msgid "results in an :exc:`!UnboundLocalError`:"
msgstr ""

msgid ""
"This is because when you make an assignment to a variable in a scope, that "
"variable becomes local to that scope and shadows any similarly named "
"variable in the outer scope.  Since the last statement in foo assigns a new "
"value to ``x``, the compiler recognizes it as a local variable.  "
"Consequently when the earlier ``print(x)`` attempts to print the "
"uninitialized local variable and an error results."
msgstr ""

msgid ""
"In the example above you can access the outer scope variable by declaring it "
"global:"
msgstr ""

msgid ""
"This explicit declaration is required in order to remind you that (unlike "
"the superficially analogous situation with class and instance variables) you "
"are actually modifying the value of the variable in the outer scope:"
msgstr ""

msgid ""
"You can do a similar thing in a nested scope using the :keyword:`nonlocal` "
"keyword:"
msgstr ""

msgid "What are the rules for local and global variables in Python?"
msgstr ""

msgid ""
"In Python, variables that are only referenced inside a function are "
"implicitly global.  If a variable is assigned a value anywhere within the "
"function's body, it's assumed to be a local unless explicitly declared as "
"global."
msgstr ""

msgid ""
"Though a bit surprising at first, a moment's consideration explains this.  "
"On one hand, requiring :keyword:`global` for assigned variables provides a "
"bar against unintended side-effects.  On the other hand, if ``global`` was "
"required for all global references, you'd be using ``global`` all the time.  "
"You'd have to declare as global every reference to a built-in function or to "
"a component of an imported module.  This clutter would defeat the usefulness "
"of the ``global`` declaration for identifying side-effects."
msgstr ""

msgid ""
"Why do lambdas defined in a loop with different values all return the same "
"result?"
msgstr ""

msgid ""
"Assume you use a for loop to define a few different lambdas (or even plain "
"functions), e.g.::"
msgstr ""

msgid ""
">>> squares = []\n"
">>> for x in range(5):\n"
"...     squares.append(lambda: x**2)"
msgstr ""
">>> squares = []\n"
">>> for x in range(5):\n"
"...     squares.append(lambda: x**2)"

msgid ""
"This gives you a list that contains 5 lambdas that calculate ``x**2``.  You "
"might expect that, when called, they would return, respectively, ``0``, "
"``1``, ``4``, ``9``, and ``16``.  However, when you actually try you will "
"see that they all return ``16``::"
msgstr ""

msgid ""
">>> squares[2]()\n"
"16\n"
">>> squares[4]()\n"
"16"
msgstr ""
">>> squares[2]()\n"
"16\n"
">>> squares[4]()\n"
"16"

msgid ""
"This happens because ``x`` is not local to the lambdas, but is defined in "
"the outer scope, and it is accessed when the lambda is called --- not when "
"it is defined.  At the end of the loop, the value of ``x`` is ``4``, so all "
"the functions now return ``4**2``, i.e. ``16``.  You can also verify this by "
"changing the value of ``x`` and see how the results of the lambdas change::"
msgstr ""

msgid ""
">>> x = 8\n"
">>> squares[2]()\n"
"64"
msgstr ""
">>> x = 8\n"
">>> squares[2]()\n"
"64"

msgid ""
"In order to avoid this, you need to save the values in variables local to "
"the lambdas, so that they don't rely on the value of the global ``x``::"
msgstr ""

msgid ""
">>> squares = []\n"
">>> for x in range(5):\n"
"...     squares.append(lambda n=x: n**2)"
msgstr ""
">>> squares = []\n"
">>> for x in range(5):\n"
"...     squares.append(lambda n=x: n**2)"

msgid ""
"Here, ``n=x`` creates a new variable ``n`` local to the lambda and computed "
"when the lambda is defined so that it has the same value that ``x`` had at "
"that point in the loop.  This means that the value of ``n`` will be ``0`` in "
"the first lambda, ``1`` in the second, ``2`` in the third, and so on. "
"Therefore each lambda will now return the correct result::"
msgstr ""

msgid ""
">>> squares[2]()\n"
"4\n"
">>> squares[4]()\n"
"16"
msgstr ""
">>> squares[2]()\n"
"4\n"
">>> squares[4]()\n"
"16"

msgid ""
"Note that this behaviour is not peculiar to lambdas, but applies to regular "
"functions too."
msgstr ""

msgid "How do I share global variables across modules?"
msgstr ""

msgid ""
"The canonical way to share information across modules within a single "
"program is to create a special module (often called config or cfg).  Just "
"import the config module in all modules of your application; the module then "
"becomes available as a global name.  Because there is only one instance of "
"each module, any changes made to the module object get reflected "
"everywhere.  For example:"
msgstr ""

msgid "config.py::"
msgstr "config.py::"

msgid "x = 0   # Default value of the 'x' configuration setting"
msgstr ""

msgid "mod.py::"
msgstr "mod.py::"

msgid ""
"import config\n"
"config.x = 1"
msgstr ""

msgid "main.py::"
msgstr "main.py::"

msgid ""
"import config\n"
"import mod\n"
"print(config.x)"
msgstr ""

msgid ""
"Note that using a module is also the basis for implementing the singleton "
"design pattern, for the same reason."
msgstr ""

msgid "What are the \"best practices\" for using import in a module?"
msgstr ""

msgid ""
"In general, don't use ``from modulename import *``.  Doing so clutters the "
"importer's namespace, and makes it much harder for linters to detect "
"undefined names."
msgstr ""

msgid ""
"Import modules at the top of a file.  Doing so makes it clear what other "
"modules your code requires and avoids questions of whether the module name "
"is in scope. Using one import per line makes it easy to add and delete "
"module imports, but using multiple imports per line uses less screen space."
msgstr ""

msgid "It's good practice if you import modules in the following order:"
msgstr ""

msgid ""
"standard library modules -- e.g. :mod:`sys`, :mod:`os`, :mod:`argparse`, :"
"mod:`re`"
msgstr ""

msgid ""
"third-party library modules (anything installed in Python's site-packages "
"directory) -- e.g. :mod:`!dateutil`, :mod:`!requests`, :mod:`!PIL.Image`"
msgstr ""

msgid "locally developed modules"
msgstr ""

msgid ""
"It is sometimes necessary to move imports to a function or class to avoid "
"problems with circular imports.  Gordon McMillan says:"
msgstr ""

msgid ""
"Circular imports are fine where both modules use the \"import <module>\" "
"form of import.  They fail when the 2nd module wants to grab a name out of "
"the first (\"from module import name\") and the import is at the top level.  "
"That's because names in the 1st are not yet available, because the first "
"module is busy importing the 2nd."
msgstr ""

msgid ""
"In this case, if the second module is only used in one function, then the "
"import can easily be moved into that function.  By the time the import is "
"called, the first module will have finished initializing, and the second "
"module can do its import."
msgstr ""

msgid ""
"It may also be necessary to move imports out of the top level of code if "
"some of the modules are platform-specific.  In that case, it may not even be "
"possible to import all of the modules at the top of the file.  In this case, "
"importing the correct modules in the corresponding platform-specific code is "
"a good option."
msgstr ""

msgid ""
"Only move imports into a local scope, such as inside a function definition, "
"if it's necessary to solve a problem such as avoiding a circular import or "
"are trying to reduce the initialization time of a module.  This technique is "
"especially helpful if many of the imports are unnecessary depending on how "
"the program executes.  You may also want to move imports into a function if "
"the modules are only ever used in that function.  Note that loading a module "
"the first time may be expensive because of the one time initialization of "
"the module, but loading a module multiple times is virtually free, costing "
"only a couple of dictionary lookups.  Even if the module name has gone out "
"of scope, the module is probably available in :data:`sys.modules`."
msgstr ""

msgid "Why are default values shared between objects?"
msgstr ""

msgid ""
"This type of bug commonly bites neophyte programmers.  Consider this "
"function::"
msgstr ""

msgid ""
"def foo(mydict={}):  # Danger: shared reference to one dict for all calls\n"
"    ... compute something ...\n"
"    mydict[key] = value\n"
"    return mydict"
msgstr ""

msgid ""
"The first time you call this function, ``mydict`` contains a single item.  "
"The second time, ``mydict`` contains two items because when ``foo()`` begins "
"executing, ``mydict`` starts out with an item already in it."
msgstr ""

msgid ""
"It is often expected that a function call creates new objects for default "
"values. This is not what happens. Default values are created exactly once, "
"when the function is defined.  If that object is changed, like the "
"dictionary in this example, subsequent calls to the function will refer to "
"this changed object."
msgstr ""

msgid ""
"By definition, immutable objects such as numbers, strings, tuples, and "
"``None``, are safe from change. Changes to mutable objects such as "
"dictionaries, lists, and class instances can lead to confusion."
msgstr ""

msgid ""
"Because of this feature, it is good programming practice to not use mutable "
"objects as default values.  Instead, use ``None`` as the default value and "
"inside the function, check if the parameter is ``None`` and create a new "
"list/dictionary/whatever if it is.  For example, don't write::"
msgstr ""

msgid ""
"def foo(mydict={}):\n"
"    ..."
msgstr ""

msgid "but::"
msgstr "ale:"

msgid ""
"def foo(mydict=None):\n"
"    if mydict is None:\n"
"        mydict = {}  # create a new dict for local namespace"
msgstr ""

msgid ""
"This feature can be useful.  When you have a function that's time-consuming "
"to compute, a common technique is to cache the parameters and the resulting "
"value of each call to the function, and return the cached value if the same "
"value is requested again.  This is called \"memoizing\", and can be "
"implemented like this::"
msgstr ""

msgid ""
"# Callers can only provide two parameters and optionally pass _cache by "
"keyword\n"
"def expensive(arg1, arg2, *, _cache={}):\n"
"    if (arg1, arg2) in _cache:\n"
"        return _cache[(arg1, arg2)]\n"
"\n"
"    # Calculate the value\n"
"    result = ... expensive computation ...\n"
"    _cache[(arg1, arg2)] = result           # Store result in the cache\n"
"    return result"
msgstr ""

msgid ""
"You could use a global variable containing a dictionary instead of the "
"default value; it's a matter of taste."
msgstr ""

msgid ""
"How can I pass optional or keyword parameters from one function to another?"
msgstr ""

msgid ""
"Collect the arguments using the ``*`` and ``**`` specifiers in the "
"function's parameter list; this gives you the positional arguments as a "
"tuple and the keyword arguments as a dictionary.  You can then pass these "
"arguments when calling another function by using ``*`` and ``**``::"
msgstr ""

msgid ""
"def f(x, *args, **kwargs):\n"
"    ...\n"
"    kwargs['width'] = '14.3c'\n"
"    ...\n"
"    g(x, *args, **kwargs)"
msgstr ""

msgid "What is the difference between arguments and parameters?"
msgstr "Jaka jest różnica pomiędzy argumentami a parametrami?"

msgid ""
":term:`Parameters <parameter>` are defined by the names that appear in a "
"function definition, whereas :term:`arguments <argument>` are the values "
"actually passed to a function when calling it.  Parameters define what :term:"
"`kind of arguments <parameter>` a function can accept.  For example, given "
"the function definition::"
msgstr ""

msgid ""
"def func(foo, bar=None, **kwargs):\n"
"    pass"
msgstr ""

msgid ""
"*foo*, *bar* and *kwargs* are parameters of ``func``.  However, when calling "
"``func``, for example::"
msgstr ""

msgid "func(42, bar=314, extra=somevar)"
msgstr ""

msgid "the values ``42``, ``314``, and ``somevar`` are arguments."
msgstr ""

msgid "Why did changing list 'y' also change list 'x'?"
msgstr ""

msgid "If you wrote code like::"
msgstr ""

msgid ""
">>> x = []\n"
">>> y = x\n"
">>> y.append(10)\n"
">>> y\n"
"[10]\n"
">>> x\n"
"[10]"
msgstr ""
">>> x = []\n"
">>> y = x\n"
">>> y.append(10)\n"
">>> y\n"
"[10]\n"
">>> x\n"
"[10]"

msgid ""
"you might be wondering why appending an element to ``y`` changed ``x`` too."
msgstr ""

msgid "There are two factors that produce this result:"
msgstr ""

msgid ""
"Variables are simply names that refer to objects.  Doing ``y = x`` doesn't "
"create a copy of the list -- it creates a new variable ``y`` that refers to "
"the same object ``x`` refers to.  This means that there is only one object "
"(the list), and both ``x`` and ``y`` refer to it."
msgstr ""

msgid ""
"Lists are :term:`mutable`, which means that you can change their content."
msgstr ""

msgid ""
"After the call to :meth:`!append`, the content of the mutable object has "
"changed from ``[]`` to ``[10]``.  Since both the variables refer to the same "
"object, using either name accesses the modified value ``[10]``."
msgstr ""

msgid "If we instead assign an immutable object to ``x``::"
msgstr ""

msgid ""
">>> x = 5  # ints are immutable\n"
">>> y = x\n"
">>> x = x + 1  # 5 can't be mutated, we are creating a new object here\n"
">>> x\n"
"6\n"
">>> y\n"
"5"
msgstr ""

msgid ""
"we can see that in this case ``x`` and ``y`` are not equal anymore.  This is "
"because integers are :term:`immutable`, and when we do ``x = x + 1`` we are "
"not mutating the int ``5`` by incrementing its value; instead, we are "
"creating a new object (the int ``6``) and assigning it to ``x`` (that is, "
"changing which object ``x`` refers to).  After this assignment we have two "
"objects (the ints ``6`` and ``5``) and two variables that refer to them "
"(``x`` now refers to ``6`` but ``y`` still refers to ``5``)."
msgstr ""

msgid ""
"Some operations (for example ``y.append(10)`` and ``y.sort()``) mutate the "
"object, whereas superficially similar operations (for example ``y = y + "
"[10]`` and :func:`sorted(y) <sorted>`) create a new object.  In general in "
"Python (and in all cases in the standard library) a method that mutates an "
"object will return ``None`` to help avoid getting the two types of "
"operations confused.  So if you mistakenly write ``y.sort()`` thinking it "
"will give you a sorted copy of ``y``, you'll instead end up with ``None``, "
"which will likely cause your program to generate an easily diagnosed error."
msgstr ""

msgid ""
"However, there is one class of operations where the same operation sometimes "
"has different behaviors with different types:  the augmented assignment "
"operators.  For example, ``+=`` mutates lists but not tuples or ints "
"(``a_list += [1, 2, 3]`` is equivalent to ``a_list.extend([1, 2, 3])`` and "
"mutates ``a_list``, whereas ``some_tuple += (1, 2, 3)`` and ``some_int += "
"1`` create new objects)."
msgstr ""

msgid "In other words:"
msgstr "Innymi słowami:"

msgid ""
"If we have a mutable object (:class:`list`, :class:`dict`, :class:`set`, "
"etc.), we can use some specific operations to mutate it and all the "
"variables that refer to it will see the change."
msgstr ""

msgid ""
"If we have an immutable object (:class:`str`, :class:`int`, :class:`tuple`, "
"etc.), all the variables that refer to it will always see the same value, "
"but operations that transform that value into a new value always return a "
"new object."
msgstr ""

msgid ""
"If you want to know if two variables refer to the same object or not, you "
"can use the :keyword:`is` operator, or the built-in function :func:`id`."
msgstr ""

msgid "How do I write a function with output parameters (call by reference)?"
msgstr ""

msgid ""
"Remember that arguments are passed by assignment in Python.  Since "
"assignment just creates references to objects, there's no alias between an "
"argument name in the caller and callee, and so no call-by-reference per se.  "
"You can achieve the desired effect in a number of ways."
msgstr ""

msgid "By returning a tuple of the results::"
msgstr ""

msgid ""
">>> def func1(a, b):\n"
"...     a = 'new-value'        # a and b are local names\n"
"...     b = b + 1              # assigned to new objects\n"
"...     return a, b            # return new values\n"
"...\n"
">>> x, y = 'old-value', 99\n"
">>> func1(x, y)\n"
"('new-value', 100)"
msgstr ""

msgid "This is almost always the clearest solution."
msgstr ""

msgid ""
"By using global variables.  This isn't thread-safe, and is not recommended."
msgstr ""

msgid "By passing a mutable (changeable in-place) object::"
msgstr ""

msgid ""
">>> def func2(a):\n"
"...     a[0] = 'new-value'     # 'a' references a mutable list\n"
"...     a[1] = a[1] + 1        # changes a shared object\n"
"...\n"
">>> args = ['old-value', 99]\n"
">>> func2(args)\n"
">>> args\n"
"['new-value', 100]"
msgstr ""

msgid "By passing in a dictionary that gets mutated::"
msgstr ""

msgid ""
">>> def func3(args):\n"
"...     args['a'] = 'new-value'     # args is a mutable dictionary\n"
"...     args['b'] = args['b'] + 1   # change it in-place\n"
"...\n"
">>> args = {'a': 'old-value', 'b': 99}\n"
">>> func3(args)\n"
">>> args\n"
"{'a': 'new-value', 'b': 100}"
msgstr ""

msgid "Or bundle up values in a class instance::"
msgstr ""

msgid ""
">>> class Namespace:\n"
"...     def __init__(self, /, **args):\n"
"...         for key, value in args.items():\n"
"...             setattr(self, key, value)\n"
"...\n"
">>> def func4(args):\n"
"...     args.a = 'new-value'        # args is a mutable Namespace\n"
"...     args.b = args.b + 1         # change object in-place\n"
"...\n"
">>> args = Namespace(a='old-value', b=99)\n"
">>> func4(args)\n"
">>> vars(args)\n"
"{'a': 'new-value', 'b': 100}"
msgstr ""

msgid "There's almost never a good reason to get this complicated."
msgstr ""

msgid "Your best choice is to return a tuple containing the multiple results."
msgstr ""

msgid "How do you make a higher order function in Python?"
msgstr ""

msgid ""
"You have two choices: you can use nested scopes or you can use callable "
"objects. For example, suppose you wanted to define ``linear(a,b)`` which "
"returns a function ``f(x)`` that computes the value ``a*x+b``.  Using nested "
"scopes::"
msgstr ""

msgid ""
"def linear(a, b):\n"
"    def result(x):\n"
"        return a * x + b\n"
"    return result"
msgstr ""

msgid "Or using a callable object::"
msgstr ""

msgid ""
"class linear:\n"
"\n"
"    def __init__(self, a, b):\n"
"        self.a, self.b = a, b\n"
"\n"
"    def __call__(self, x):\n"
"        return self.a * x + self.b"
msgstr ""

msgid "In both cases, ::"
msgstr "W obydwu przypadkach, ::"

msgid "taxes = linear(0.3, 2)"
msgstr ""

msgid "gives a callable object where ``taxes(10e6) == 0.3 * 10e6 + 2``."
msgstr ""

msgid ""
"The callable object approach has the disadvantage that it is a bit slower "
"and results in slightly longer code.  However, note that a collection of "
"callables can share their signature via inheritance::"
msgstr ""

msgid ""
"class exponential(linear):\n"
"    # __init__ inherited\n"
"    def __call__(self, x):\n"
"        return self.a * (x ** self.b)"
msgstr ""

msgid "Object can encapsulate state for several methods::"
msgstr ""

msgid ""
"class counter:\n"
"\n"
"    value = 0\n"
"\n"
"    def set(self, x):\n"
"        self.value = x\n"
"\n"
"    def up(self):\n"
"        self.value = self.value + 1\n"
"\n"
"    def down(self):\n"
"        self.value = self.value - 1\n"
"\n"
"count = counter()\n"
"inc, dec, reset = count.up, count.down, count.set"
msgstr ""

msgid ""
"Here ``inc()``, ``dec()`` and ``reset()`` act like functions which share the "
"same counting variable."
msgstr ""

msgid "How do I copy an object in Python?"
msgstr "Jak mogę skopiować obiekt w Pythonie?"

msgid ""
"In general, try :func:`copy.copy` or :func:`copy.deepcopy` for the general "
"case. Not all objects can be copied, but most can."
msgstr ""

msgid ""
"Some objects can be copied more easily.  Dictionaries have a :meth:`~dict."
"copy` method::"
msgstr ""

msgid "newdict = olddict.copy()"
msgstr ""

msgid "Sequences can be copied by slicing::"
msgstr ""

msgid "new_l = l[:]"
msgstr ""

msgid "How can I find the methods or attributes of an object?"
msgstr ""

msgid ""
"For an instance ``x`` of a user-defined class, :func:`dir(x) <dir>` returns "
"an alphabetized list of the names containing the instance attributes and "
"methods and attributes defined by its class."
msgstr ""

msgid "How can my code discover the name of an object?"
msgstr ""

msgid ""
"Generally speaking, it can't, because objects don't really have names. "
"Essentially, assignment always binds a name to a value; the same is true of "
"``def`` and ``class`` statements, but in that case the value is a callable. "
"Consider the following code::"
msgstr ""

msgid ""
">>> class A:\n"
"...     pass\n"
"...\n"
">>> B = A\n"
">>> a = B()\n"
">>> b = a\n"
">>> print(b)\n"
"<__main__.A object at 0x16D07CC>\n"
">>> print(a)\n"
"<__main__.A object at 0x16D07CC>"
msgstr ""
">>> class A:\n"
"...     pass\n"
"...\n"
">>> B = A\n"
">>> a = B()\n"
">>> b = a\n"
">>> print(b)\n"
"<__main__.A object at 0x16D07CC>\n"
">>> print(a)\n"
"<__main__.A object at 0x16D07CC>"

msgid ""
"Arguably the class has a name: even though it is bound to two names and "
"invoked through the name ``B`` the created instance is still reported as an "
"instance of class ``A``.  However, it is impossible to say whether the "
"instance's name is ``a`` or ``b``, since both names are bound to the same "
"value."
msgstr ""

msgid ""
"Generally speaking it should not be necessary for your code to \"know the "
"names\" of particular values. Unless you are deliberately writing "
"introspective programs, this is usually an indication that a change of "
"approach might be beneficial."
msgstr ""

msgid ""
"In comp.lang.python, Fredrik Lundh once gave an excellent analogy in answer "
"to this question:"
msgstr ""

msgid ""
"The same way as you get the name of that cat you found on your porch: the "
"cat (object) itself cannot tell you its name, and it doesn't really care -- "
"so the only way to find out what it's called is to ask all your neighbours "
"(namespaces) if it's their cat (object)..."
msgstr ""

msgid ""
"....and don't be surprised if you'll find that it's known by many names, or "
"no name at all!"
msgstr ""

msgid "What's up with the comma operator's precedence?"
msgstr ""

msgid "Comma is not an operator in Python.  Consider this session::"
msgstr ""

msgid ""
">>> \"a\" in \"b\", \"a\"\n"
"(False, 'a')"
msgstr ""
">>> \"a\" in \"b\", \"a\"\n"
"(False, 'a')"

msgid ""
"Since the comma is not an operator, but a separator between expressions the "
"above is evaluated as if you had entered::"
msgstr ""

msgid "(\"a\" in \"b\"), \"a\""
msgstr ""

msgid "not::"
msgstr ""

msgid "\"a\" in (\"b\", \"a\")"
msgstr ""

msgid ""
"The same is true of the various assignment operators (``=``, ``+=`` etc).  "
"They are not truly operators but syntactic delimiters in assignment "
"statements."
msgstr ""

msgid "Is there an equivalent of C's \"?:\" ternary operator?"
msgstr ""

msgid "Yes, there is. The syntax is as follows::"
msgstr ""

msgid ""
"[on_true] if [expression] else [on_false]\n"
"\n"
"x, y = 50, 25\n"
"small = x if x < y else y"
msgstr ""

msgid ""
"Before this syntax was introduced in Python 2.5, a common idiom was to use "
"logical operators::"
msgstr ""

msgid "[expression] and [on_true] or [on_false]"
msgstr ""

msgid ""
"However, this idiom is unsafe, as it can give wrong results when *on_true* "
"has a false boolean value.  Therefore, it is always better to use the ``... "
"if ... else ...`` form."
msgstr ""

msgid "Is it possible to write obfuscated one-liners in Python?"
msgstr "Czy w Pythonie da się napisać pokręcony jednolinijkowy kod?"

msgid ""
"Yes.  Usually this is done by nesting :keyword:`lambda` within :keyword:`!"
"lambda`.  See the following three examples, slightly adapted from Ulf "
"Bartelt::"
msgstr ""

msgid ""
"from functools import reduce\n"
"\n"
"# Primes < 1000\n"
"print(list(filter(None,map(lambda y:y*reduce(lambda x,y:x*y!=0,\n"
"map(lambda x,y=y:y%x,range(2,int(pow(y,0.5)+1))),1),range(2,1000)))))\n"
"\n"
"# First 10 Fibonacci numbers\n"
"print(list(map(lambda x,f=lambda x,f:(f(x-1,f)+f(x-2,f)) if x>1 else 1:\n"
"f(x,f), range(10))))\n"
"\n"
"# Mandelbrot set\n"
"print((lambda Ru,Ro,Iu,Io,IM,Sx,Sy:reduce(lambda x,y:x+'\\n'+y,map(lambda "
"y,\n"
"Iu=Iu,Io=Io,Ru=Ru,Ro=Ro,Sy=Sy,L=lambda yc,Iu=Iu,Io=Io,Ru=Ru,Ro=Ro,i=IM,\n"
"Sx=Sx,Sy=Sy:reduce(lambda x,y:x+y,map(lambda x,xc=Ru,yc=yc,Ru=Ru,Ro=Ro,\n"
"i=i,Sx=Sx,F=lambda xc,yc,x,y,k,f=lambda xc,yc,x,y,k,f:(k<=0)or (x*x+y*y\n"
">=4.0) or 1+f(xc,yc,x*x-y*y+xc,2.0*x*y+yc,k-1,f):f(xc,yc,x,y,k,f):chr(\n"
"64+F(Ru+x*(Ro-Ru)/Sx,yc,0,0,i)),range(Sx))):L(Iu+y*(Io-Iu)/Sy),range(Sy\n"
"))))(-2.1, 0.7, -1.2, 1.2, 30, 80, 24))\n"
"#    \\___ ___/  \\___ ___/  |   |   |__ lines on screen\n"
"#        V          V      |   |______ columns on screen\n"
"#        |          |      |__________ maximum of \"iterations\"\n"
"#        |          |_________________ range on y axis\n"
"#        |____________________________ range on x axis"
msgstr ""

msgid "Don't try this at home, kids!"
msgstr "Nie próbujcie tego w domu, dzieciaki!"

msgid "What does the slash(/) in the parameter list of a function mean?"
msgstr ""

msgid ""
"A slash in the argument list of a function denotes that the parameters prior "
"to it are positional-only.  Positional-only parameters are the ones without "
"an externally usable name.  Upon calling a function that accepts positional-"
"only parameters, arguments are mapped to parameters based solely on their "
"position. For example, :func:`divmod` is a function that accepts positional-"
"only parameters. Its documentation looks like this::"
msgstr ""

msgid ""
">>> help(divmod)\n"
"Help on built-in function divmod in module builtins:\n"
"\n"
"divmod(x, y, /)\n"
"    Return the tuple (x//y, x%y).  Invariant: div*y + mod == x."
msgstr ""

msgid ""
"The slash at the end of the parameter list means that both parameters are "
"positional-only. Thus, calling :func:`divmod` with keyword arguments would "
"lead to an error::"
msgstr ""

msgid ""
">>> divmod(x=3, y=4)\n"
"Traceback (most recent call last):\n"
"  File \"<stdin>\", line 1, in <module>\n"
"TypeError: divmod() takes no keyword arguments"
msgstr ""

msgid "Numbers and strings"
msgstr "Liczby i ciągi znaków"

msgid "How do I specify hexadecimal and octal integers?"
msgstr ""

msgid ""
"To specify an octal digit, precede the octal value with a zero, and then a "
"lower or uppercase \"o\".  For example, to set the variable \"a\" to the "
"octal value \"10\" (8 in decimal), type::"
msgstr ""

msgid ""
">>> a = 0o10\n"
">>> a\n"
"8"
msgstr ""
">>> a = 0o10\n"
">>> a\n"
"8"

msgid ""
"Hexadecimal is just as easy.  Simply precede the hexadecimal number with a "
"zero, and then a lower or uppercase \"x\".  Hexadecimal digits can be "
"specified in lower or uppercase.  For example, in the Python interpreter::"
msgstr ""

msgid ""
">>> a = 0xa5\n"
">>> a\n"
"165\n"
">>> b = 0XB2\n"
">>> b\n"
"178"
msgstr ""
">>> a = 0xa5\n"
">>> a\n"
"165\n"
">>> b = 0XB2\n"
">>> b\n"
"178"

msgid "Why does -22 // 10 return -3?"
msgstr "Dlaczego -22 // 10 zwraca -3?"

msgid ""
"It's primarily driven by the desire that ``i % j`` have the same sign as "
"``j``. If you want that, and also want::"
msgstr ""

msgid "i == (i // j) * j + (i % j)"
msgstr ""

msgid ""
"then integer division has to return the floor.  C also requires that "
"identity to hold, and then compilers that truncate ``i // j`` need to make "
"``i % j`` have the same sign as ``i``."
msgstr ""

msgid ""
"There are few real use cases for ``i % j`` when ``j`` is negative.  When "
"``j`` is positive, there are many, and in virtually all of them it's more "
"useful for ``i % j`` to be ``>= 0``.  If the clock says 10 now, what did it "
"say 200 hours ago?  ``-190 % 12 == 2`` is useful; ``-190 % 12 == -10`` is a "
"bug waiting to bite."
msgstr ""

msgid "How do I get int literal attribute instead of SyntaxError?"
msgstr ""

msgid ""
"Trying to lookup an ``int`` literal attribute in the normal manner gives a :"
"exc:`SyntaxError` because the period is seen as a decimal point::"
msgstr ""

msgid ""
">>> 1.__class__\n"
"  File \"<stdin>\", line 1\n"
"  1.__class__\n"
"   ^\n"
"SyntaxError: invalid decimal literal"
msgstr ""
">>> 1.__class__\n"
"  File \"<stdin>\", line 1\n"
"  1.__class__\n"
"   ^\n"
"SyntaxError: invalid decimal literal"

msgid ""
"The solution is to separate the literal from the period with either a space "
"or parentheses."
msgstr ""

msgid "How do I convert a string to a number?"
msgstr "Jak skonwertować ciąg znaków na liczbę?"

msgid ""
"For integers, use the built-in :func:`int` type constructor, e.g. "
"``int('144') == 144``.  Similarly, :func:`float` converts to a floating-"
"point number, e.g. ``float('144') == 144.0``."
msgstr ""

msgid ""
"By default, these interpret the number as decimal, so that ``int('0144') == "
"144`` holds true, and ``int('0x144')`` raises :exc:`ValueError`. "
"``int(string, base)`` takes the base to convert from as a second optional "
"argument, so ``int( '0x144', 16) == 324``.  If the base is specified as 0, "
"the number is interpreted using Python's rules: a leading '0o' indicates "
"octal, and '0x' indicates a hex number."
msgstr ""

msgid ""
"Do not use the built-in function :func:`eval` if all you need is to convert "
"strings to numbers.  :func:`eval` will be significantly slower and it "
"presents a security risk: someone could pass you a Python expression that "
"might have unwanted side effects.  For example, someone could pass "
"``__import__('os').system(\"rm -rf $HOME\")`` which would erase your home "
"directory."
msgstr ""

msgid ""
":func:`eval` also has the effect of interpreting numbers as Python "
"expressions, so that e.g. ``eval('09')`` gives a syntax error because Python "
"does not allow leading '0' in a decimal number (except '0')."
msgstr ""

msgid "How do I convert a number to a string?"
msgstr "Jak skonwertować liczbę na ciąg znaków?"

msgid ""
"To convert, e.g., the number ``144`` to the string ``'144'``, use the built-"
"in type constructor :func:`str`.  If you want a hexadecimal or octal "
"representation, use the built-in functions :func:`hex` or :func:`oct`.  For "
"fancy formatting, see the :ref:`f-strings` and :ref:`formatstrings` "
"sections, e.g. ``\"{:04d}\".format(144)`` yields ``'0144'`` and ``\"{:.3f}\"."
"format(1.0/3.0)`` yields ``'0.333'``."
msgstr ""

msgid "How do I modify a string in place?"
msgstr "Jak zmodyfikować ciąg znaków „w miejscu”?"

msgid ""
"You can't, because strings are immutable.  In most situations, you should "
"simply construct a new string from the various parts you want to assemble it "
"from.  However, if you need an object with the ability to modify in-place "
"unicode data, try using an :class:`io.StringIO` object or the :mod:`array` "
"module::"
msgstr ""

msgid ""
">>> import io\n"
">>> s = \"Hello, world\"\n"
">>> sio = io.StringIO(s)\n"
">>> sio.getvalue()\n"
"'Hello, world'\n"
">>> sio.seek(7)\n"
"7\n"
">>> sio.write(\"there!\")\n"
"6\n"
">>> sio.getvalue()\n"
"'Hello, there!'\n"
"\n"
">>> import array\n"
">>> a = array.array('w', s)\n"
">>> print(a)\n"
"array('w', 'Hello, world')\n"
">>> a[0] = 'y'\n"
">>> print(a)\n"
"array('w', 'yello, world')\n"
">>> a.tounicode()\n"
"'yello, world'"
msgstr ""

msgid "How do I use strings to call functions/methods?"
msgstr ""

msgid "There are various techniques."
msgstr ""

msgid ""
"The best is to use a dictionary that maps strings to functions.  The primary "
"advantage of this technique is that the strings do not need to match the "
"names of the functions.  This is also the primary technique used to emulate "
"a case construct::"
msgstr ""

msgid ""
"def a():\n"
"    pass\n"
"\n"
"def b():\n"
"    pass\n"
"\n"
"dispatch = {'go': a, 'stop': b}  # Note lack of parens for funcs\n"
"\n"
"dispatch[get_input()]()  # Note trailing parens to call function"
msgstr ""

msgid "Use the built-in function :func:`getattr`::"
msgstr ""

msgid ""
"import foo\n"
"getattr(foo, 'bar')()"
msgstr ""

msgid ""
"Note that :func:`getattr` works on any object, including classes, class "
"instances, modules, and so on."
msgstr ""

msgid "This is used in several places in the standard library, like this::"
msgstr ""

msgid ""
"class Foo:\n"
"    def do_foo(self):\n"
"        ...\n"
"\n"
"    def do_bar(self):\n"
"        ...\n"
"\n"
"f = getattr(foo_instance, 'do_' + opname)\n"
"f()"
msgstr ""

msgid "Use :func:`locals` to resolve the function name::"
msgstr ""

msgid ""
"def myFunc():\n"
"    print(\"hello\")\n"
"\n"
"fname = \"myFunc\"\n"
"\n"
"f = locals()[fname]\n"
"f()"
msgstr ""

msgid ""
"Is there an equivalent to Perl's ``chomp()`` for removing trailing newlines "
"from strings?"
msgstr ""

msgid ""
"You can use ``S.rstrip(\"\\r\\n\")`` to remove all occurrences of any line "
"terminator from the end of the string ``S`` without removing other trailing "
"whitespace.  If the string ``S`` represents more than one line, with several "
"empty lines at the end, the line terminators for all the blank lines will be "
"removed::"
msgstr ""

msgid ""
">>> lines = (\"line 1 \\r\\n\"\n"
"...          \"\\r\\n\"\n"
"...          \"\\r\\n\")\n"
">>> lines.rstrip(\"\\n\\r\")\n"
"'line 1 '"
msgstr ""
">>> lines = (\"line 1 \\r\\n\"\n"
"...          \"\\r\\n\"\n"
"...          \"\\r\\n\")\n"
">>> lines.rstrip(\"\\n\\r\")\n"
"'line 1 '"

msgid ""
"Since this is typically only desired when reading text one line at a time, "
"using ``S.rstrip()`` this way works well."
msgstr ""

msgid "Is there a ``scanf()`` or ``sscanf()`` equivalent?"
msgstr ""

msgid "Not as such."
msgstr ""

msgid ""
"For simple input parsing, the easiest approach is usually to split the line "
"into whitespace-delimited words using the :meth:`~str.split` method of "
"string objects and then convert decimal strings to numeric values using :"
"func:`int` or :func:`float`.  :meth:`!split` supports an optional \"sep\" "
"parameter which is useful if the line uses something other than whitespace "
"as a separator."
msgstr ""

msgid ""
"For more complicated input parsing, regular expressions are more powerful "
"than C's ``sscanf`` and better suited for the task."
msgstr ""

msgid "What does ``UnicodeDecodeError`` or ``UnicodeEncodeError`` error mean?"
msgstr ""

msgid "See the :ref:`unicode-howto`."
msgstr ""

msgid "Can I end a raw string with an odd number of backslashes?"
msgstr ""

msgid ""
"A raw string ending with an odd number of backslashes will escape the "
"string's quote::"
msgstr ""

msgid ""
">>> r'C:\\this\\will\\not\\work\\'\n"
"  File \"<stdin>\", line 1\n"
"    r'C:\\this\\will\\not\\work\\'\n"
"    ^\n"
"SyntaxError: unterminated string literal (detected at line 1)"
msgstr ""

msgid ""
"There are several workarounds for this. One is to use regular strings and "
"double the backslashes::"
msgstr ""

msgid ""
">>> 'C:\\\\this\\\\will\\\\work\\\\'\n"
"'C:\\\\this\\\\will\\\\work\\\\'"
msgstr ""

msgid ""
"Another is to concatenate a regular string containing an escaped backslash "
"to the raw string::"
msgstr ""

msgid ""
">>> r'C:\\this\\will\\work' '\\\\'\n"
"'C:\\\\this\\\\will\\\\work\\\\'"
msgstr ""
">>> r'C:\\this\\will\\work' '\\\\'\n"
"'C:\\\\this\\\\will\\\\work\\\\'"

msgid ""
"It is also possible to use :func:`os.path.join` to append a backslash on "
"Windows::"
msgstr ""

msgid ""
">>> os.path.join(r'C:\\this\\will\\work', '')\n"
"'C:\\\\this\\\\will\\\\work\\\\'"
msgstr ""
">>> os.path.join(r'C:\\this\\will\\work', '')\n"
"'C:\\\\this\\\\will\\\\work\\\\'"

msgid ""
"Note that while a backslash will \"escape\" a quote for the purposes of "
"determining where the raw string ends, no escaping occurs when interpreting "
"the value of the raw string. That is, the backslash remains present in the "
"value of the raw string::"
msgstr ""

msgid ""
">>> r'backslash\\'preserved'\n"
"\"backslash\\\\'preserved\""
msgstr ""

msgid "Also see the specification in the :ref:`language reference <strings>`."
msgstr ""

msgid "Performance"
msgstr "Wydajność"

msgid "My program is too slow. How do I speed it up?"
msgstr "Mój program jest za wolny. Jak mogę go przyspieszyć?"

msgid ""
"That's a tough one, in general.  First, here are a list of things to "
"remember before diving further:"
msgstr ""

msgid ""
"Performance characteristics vary across Python implementations.  This FAQ "
"focuses on :term:`CPython`."
msgstr ""

msgid ""
"Behaviour can vary across operating systems, especially when talking about I/"
"O or multi-threading."
msgstr ""

msgid ""
"You should always find the hot spots in your program *before* attempting to "
"optimize any code (see the :mod:`profile` module)."
msgstr ""

msgid ""
"Writing benchmark scripts will allow you to iterate quickly when searching "
"for improvements (see the :mod:`timeit` module)."
msgstr ""

msgid ""
"It is highly recommended to have good code coverage (through unit testing or "
"any other technique) before potentially introducing regressions hidden in "
"sophisticated optimizations."
msgstr ""

msgid ""
"That being said, there are many tricks to speed up Python code.  Here are "
"some general principles which go a long way towards reaching acceptable "
"performance levels:"
msgstr ""

msgid ""
"Making your algorithms faster (or changing to faster ones) can yield much "
"larger benefits than trying to sprinkle micro-optimization tricks all over "
"your code."
msgstr ""

msgid ""
"Use the right data structures.  Study documentation for the :ref:`bltin-"
"types` and the :mod:`collections` module."
msgstr ""

msgid ""
"When the standard library provides a primitive for doing something, it is "
"likely (although not guaranteed) to be faster than any alternative you may "
"come up with.  This is doubly true for primitives written in C, such as "
"builtins and some extension types.  For example, be sure to use either the :"
"meth:`list.sort` built-in method or the related :func:`sorted` function to "
"do sorting (and see the :ref:`sortinghowto` for examples of moderately "
"advanced usage)."
msgstr ""

msgid ""
"Abstractions tend to create indirections and force the interpreter to work "
"more.  If the levels of indirection outweigh the amount of useful work done, "
"your program will be slower.  You should avoid excessive abstraction, "
"especially under the form of tiny functions or methods (which are also often "
"detrimental to readability)."
msgstr ""

msgid ""
"If you have reached the limit of what pure Python can allow, there are tools "
"to take you further away.  For example, `Cython <https://cython.org>`_ can "
"compile a slightly modified version of Python code into a C extension, and "
"can be used on many different platforms.  Cython can take advantage of "
"compilation (and optional type annotations) to make your code significantly "
"faster than when interpreted.  If you are confident in your C programming "
"skills, you can also :ref:`write a C extension module <extending-index>` "
"yourself."
msgstr ""

msgid ""
"The wiki page devoted to `performance tips <https://wiki.python.org/moin/"
"PythonSpeed/PerformanceTips>`_."
msgstr ""

msgid "What is the most efficient way to concatenate many strings together?"
msgstr ""

msgid ""
":class:`str` and :class:`bytes` objects are immutable, therefore "
"concatenating many strings together is inefficient as each concatenation "
"creates a new object.  In the general case, the total runtime cost is "
"quadratic in the total string length."
msgstr ""

msgid ""
"To accumulate many :class:`str` objects, the recommended idiom is to place "
"them into a list and call :meth:`str.join` at the end::"
msgstr ""

msgid ""
"chunks = []\n"
"for s in my_strings:\n"
"    chunks.append(s)\n"
"result = ''.join(chunks)"
msgstr ""

msgid "(another reasonably efficient idiom is to use :class:`io.StringIO`)"
msgstr ""

msgid ""
"To accumulate many :class:`bytes` objects, the recommended idiom is to "
"extend a :class:`bytearray` object using in-place concatenation (the ``+=`` "
"operator)::"
msgstr ""

msgid ""
"result = bytearray()\n"
"for b in my_bytes_objects:\n"
"    result += b"
msgstr ""

msgid "Sequences (Tuples/Lists)"
msgstr ""

msgid "How do I convert between tuples and lists?"
msgstr ""

msgid ""
"The type constructor ``tuple(seq)`` converts any sequence (actually, any "
"iterable) into a tuple with the same items in the same order."
msgstr ""

msgid ""
"For example, ``tuple([1, 2, 3])`` yields ``(1, 2, 3)`` and ``tuple('abc')`` "
"yields ``('a', 'b', 'c')``.  If the argument is a tuple, it does not make a "
"copy but returns the same object, so it is cheap to call :func:`tuple` when "
"you aren't sure that an object is already a tuple."
msgstr ""

msgid ""
"The type constructor ``list(seq)`` converts any sequence or iterable into a "
"list with the same items in the same order.  For example, ``list((1, 2, "
"3))`` yields ``[1, 2, 3]`` and ``list('abc')`` yields ``['a', 'b', 'c']``.  "
"If the argument is a list, it makes a copy just like ``seq[:]`` would."
msgstr ""

msgid "What's a negative index?"
msgstr ""

msgid ""
"Python sequences are indexed with positive numbers and negative numbers.  "
"For positive numbers 0 is the first index 1 is the second index and so "
"forth.  For negative indices -1 is the last index and -2 is the penultimate "
"(next to last) index and so forth.  Think of ``seq[-n]`` as the same as "
"``seq[len(seq)-n]``."
msgstr ""

msgid ""
"Using negative indices can be very convenient.  For example ``S[:-1]`` is "
"all of the string except for its last character, which is useful for "
"removing the trailing newline from a string."
msgstr ""

msgid "How do I iterate over a sequence in reverse order?"
msgstr ""

msgid "Use the :func:`reversed` built-in function::"
msgstr ""

msgid ""
"for x in reversed(sequence):\n"
"    ...  # do something with x ..."
msgstr ""

msgid ""
"This won't touch your original sequence, but build a new copy with reversed "
"order to iterate over."
msgstr ""

msgid "How do you remove duplicates from a list?"
msgstr "Jak usuwasz duplikaty z listy?"

msgid "See the Python Cookbook for a long discussion of many ways to do this:"
msgstr ""

msgid "https://code.activestate.com/recipes/52560/"
msgstr "https://code.activestate.com/recipes/52560/"

msgid ""
"If you don't mind reordering the list, sort it and then scan from the end of "
"the list, deleting duplicates as you go::"
msgstr ""

msgid ""
"if mylist:\n"
"    mylist.sort()\n"
"    last = mylist[-1]\n"
"    for i in range(len(mylist)-2, -1, -1):\n"
"        if last == mylist[i]:\n"
"            del mylist[i]\n"
"        else:\n"
"            last = mylist[i]"
msgstr ""

msgid ""
"If all elements of the list may be used as set keys (i.e. they are all :term:"
"`hashable`) this is often faster ::"
msgstr ""

msgid "mylist = list(set(mylist))"
msgstr ""

msgid ""
"This converts the list into a set, thereby removing duplicates, and then "
"back into a list."
msgstr ""

msgid "How do you remove multiple items from a list"
msgstr ""

msgid ""
"As with removing duplicates, explicitly iterating in reverse with a delete "
"condition is one possibility.  However, it is easier and faster to use slice "
"replacement with an implicit or explicit forward iteration. Here are three "
"variations.::"
msgstr ""

msgid ""
"mylist[:] = filter(keep_function, mylist)\n"
"mylist[:] = (x for x in mylist if keep_condition)\n"
"mylist[:] = [x for x in mylist if keep_condition]"
msgstr ""

msgid "The list comprehension may be fastest."
msgstr ""

msgid "How do you make an array in Python?"
msgstr "Jak zrobić tablicę w Pythonie?"

msgid "Use a list::"
msgstr ""

msgid "[\"this\", 1, \"is\", \"an\", \"array\"]"
msgstr ""

msgid ""
"Lists are equivalent to C or Pascal arrays in their time complexity; the "
"primary difference is that a Python list can contain objects of many "
"different types."
msgstr ""

msgid ""
"The ``array`` module also provides methods for creating arrays of fixed "
"types with compact representations, but they are slower to index than "
"lists.  Also note that `NumPy <https://numpy.org/>`_ and other third party "
"packages define array-like structures with various characteristics as well."
msgstr ""

msgid ""
"To get Lisp-style linked lists, you can emulate *cons cells* using tuples::"
msgstr ""

msgid "lisp_list = (\"like\",  (\"this\",  (\"example\", None) ) )"
msgstr ""

msgid ""
"If mutability is desired, you could use lists instead of tuples.  Here the "
"analogue of a Lisp *car* is ``lisp_list[0]`` and the analogue of *cdr* is "
"``lisp_list[1]``.  Only do this if you're sure you really need to, because "
"it's usually a lot slower than using Python lists."
msgstr ""

msgid "How do I create a multidimensional list?"
msgstr "Jak stworzyć listę wielowymiarową?"

msgid "You probably tried to make a multidimensional array like this::"
msgstr ""

msgid ">>> A = [[None] * 2] * 3"
msgstr ">>> A = [[None] * 2] * 3"

msgid "This looks correct if you print it:"
msgstr ""

msgid ""
">>> A\n"
"[[None, None], [None, None], [None, None]]"
msgstr ""
">>> A\n"
"[[None, None], [None, None], [None, None]]"

msgid "But when you assign a value, it shows up in multiple places:"
msgstr ""

msgid ""
">>> A[0][0] = 5\n"
">>> A\n"
"[[5, None], [5, None], [5, None]]"
msgstr ""
">>> A[0][0] = 5\n"
">>> A\n"
"[[5, None], [5, None], [5, None]]"

msgid ""
"The reason is that replicating a list with ``*`` doesn't create copies, it "
"only creates references to the existing objects.  The ``*3`` creates a list "
"containing 3 references to the same list of length two.  Changes to one row "
"will show in all rows, which is almost certainly not what you want."
msgstr ""

msgid ""
"The suggested approach is to create a list of the desired length first and "
"then fill in each element with a newly created list::"
msgstr ""

msgid ""
"A = [None] * 3\n"
"for i in range(3):\n"
"    A[i] = [None] * 2"
msgstr ""

msgid ""
"This generates a list containing 3 different lists of length two.  You can "
"also use a list comprehension::"
msgstr ""

msgid ""
"w, h = 2, 3\n"
"A = [[None] * w for i in range(h)]"
msgstr ""

msgid ""
"Or, you can use an extension that provides a matrix datatype; `NumPy "
"<https://numpy.org/>`_ is the best known."
msgstr ""

msgid "How do I apply a method or function to a sequence of objects?"
msgstr ""

msgid ""
"To call a method or function and accumulate the return values is a list, a :"
"term:`list comprehension` is an elegant solution::"
msgstr ""

msgid ""
"result = [obj.method() for obj in mylist]\n"
"\n"
"result = [function(obj) for obj in mylist]"
msgstr ""

msgid ""
"To just run the method or function without saving the return values, a "
"plain :keyword:`for` loop will suffice::"
msgstr ""

msgid ""
"for obj in mylist:\n"
"    obj.method()\n"
"\n"
"for obj in mylist:\n"
"    function(obj)"
msgstr ""

msgid ""
"Why does a_tuple[i] += ['item'] raise an exception when the addition works?"
msgstr ""

msgid ""
"This is because of a combination of the fact that augmented assignment "
"operators are *assignment* operators, and the difference between mutable and "
"immutable objects in Python."
msgstr ""

msgid ""
"This discussion applies in general when augmented assignment operators are "
"applied to elements of a tuple that point to mutable objects, but we'll use "
"a ``list`` and ``+=`` as our exemplar."
msgstr ""

msgid "If you wrote::"
msgstr ""

msgid ""
">>> a_tuple = (1, 2)\n"
">>> a_tuple[0] += 1\n"
"Traceback (most recent call last):\n"
"   ...\n"
"TypeError: 'tuple' object does not support item assignment"
msgstr ""
">>> a_tuple = (1, 2)\n"
">>> a_tuple[0] += 1\n"
"Traceback (most recent call last):\n"
"   ...\n"
"TypeError: 'tuple' object does not support item assignment"

msgid ""
"The reason for the exception should be immediately clear: ``1`` is added to "
"the object ``a_tuple[0]`` points to (``1``), producing the result object, "
"``2``, but when we attempt to assign the result of the computation, ``2``, "
"to element ``0`` of the tuple, we get an error because we can't change what "
"an element of a tuple points to."
msgstr ""

msgid ""
"Under the covers, what this augmented assignment statement is doing is "
"approximately this::"
msgstr ""

msgid ""
">>> result = a_tuple[0] + 1\n"
">>> a_tuple[0] = result\n"
"Traceback (most recent call last):\n"
"  ...\n"
"TypeError: 'tuple' object does not support item assignment"
msgstr ""
">>> result = a_tuple[0] + 1\n"
">>> a_tuple[0] = result\n"
"Traceback (most recent call last):\n"
"  ...\n"
"TypeError: 'tuple' object does not support item assignment"

msgid ""
"It is the assignment part of the operation that produces the error, since a "
"tuple is immutable."
msgstr ""

msgid "When you write something like::"
msgstr ""

msgid ""
">>> a_tuple = (['foo'], 'bar')\n"
">>> a_tuple[0] += ['item']\n"
"Traceback (most recent call last):\n"
"  ...\n"
"TypeError: 'tuple' object does not support item assignment"
msgstr ""
">>> a_tuple = (['foo'], 'bar')\n"
">>> a_tuple[0] += ['item']\n"
"Traceback (most recent call last):\n"
"  ...\n"
"TypeError: 'tuple' object does not support item assignment"

msgid ""
"The exception is a bit more surprising, and even more surprising is the fact "
"that even though there was an error, the append worked::"
msgstr ""

msgid ""
">>> a_tuple[0]\n"
"['foo', 'item']"
msgstr ""
">>> a_tuple[0]\n"
"['foo', 'item']"

msgid ""
"To see why this happens, you need to know that (a) if an object implements "
"an :meth:`~object.__iadd__` magic method, it gets called when the ``+=`` "
"augmented assignment is executed, and its return value is what gets used in "
"the assignment statement; and (b) for lists, :meth:`!__iadd__` is equivalent "
"to calling :meth:`!extend` on the list and returning the list.  That's why "
"we say that for lists, ``+=`` is a \"shorthand\" for :meth:`!list.extend`::"
msgstr ""

msgid ""
">>> a_list = []\n"
">>> a_list += [1]\n"
">>> a_list\n"
"[1]"
msgstr ""
">>> a_list = []\n"
">>> a_list += [1]\n"
">>> a_list\n"
"[1]"

msgid "This is equivalent to::"
msgstr ""

msgid ""
">>> result = a_list.__iadd__([1])\n"
">>> a_list = result"
msgstr ""
">>> result = a_list.__iadd__([1])\n"
">>> a_list = result"

msgid ""
"The object pointed to by a_list has been mutated, and the pointer to the "
"mutated object is assigned back to ``a_list``.  The end result of the "
"assignment is a no-op, since it is a pointer to the same object that "
"``a_list`` was previously pointing to, but the assignment still happens."
msgstr ""

msgid "Thus, in our tuple example what is happening is equivalent to::"
msgstr ""

msgid ""
">>> result = a_tuple[0].__iadd__(['item'])\n"
">>> a_tuple[0] = result\n"
"Traceback (most recent call last):\n"
"  ...\n"
"TypeError: 'tuple' object does not support item assignment"
msgstr ""
">>> result = a_tuple[0].__iadd__(['item'])\n"
">>> a_tuple[0] = result\n"
"Traceback (most recent call last):\n"
"  ...\n"
"TypeError: 'tuple' object does not support item assignment"

msgid ""
"The :meth:`!__iadd__` succeeds, and thus the list is extended, but even "
"though ``result`` points to the same object that ``a_tuple[0]`` already "
"points to, that final assignment still results in an error, because tuples "
"are immutable."
msgstr ""

msgid ""
"I want to do a complicated sort: can you do a Schwartzian Transform in "
"Python?"
msgstr ""

msgid ""
"The technique, attributed to Randal Schwartz of the Perl community, sorts "
"the elements of a list by a metric which maps each element to its \"sort "
"value\". In Python, use the ``key`` argument for the :meth:`list.sort` "
"method::"
msgstr ""

msgid ""
"Isorted = L[:]\n"
"Isorted.sort(key=lambda s: int(s[10:15]))"
msgstr ""

msgid "How can I sort one list by values from another list?"
msgstr ""

msgid ""
"Merge them into an iterator of tuples, sort the resulting list, and then "
"pick out the element you want. ::"
msgstr ""

msgid ""
">>> list1 = [\"what\", \"I'm\", \"sorting\", \"by\"]\n"
">>> list2 = [\"something\", \"else\", \"to\", \"sort\"]\n"
">>> pairs = zip(list1, list2)\n"
">>> pairs = sorted(pairs)\n"
">>> pairs\n"
"[(\"I'm\", 'else'), ('by', 'sort'), ('sorting', 'to'), ('what', "
"'something')]\n"
">>> result = [x[1] for x in pairs]\n"
">>> result\n"
"['else', 'sort', 'to', 'something']"
msgstr ""
">>> list1 = [\"what\", \"I'm\", \"sorting\", \"by\"]\n"
">>> list2 = [\"something\", \"else\", \"to\", \"sort\"]\n"
">>> pairs = zip(list1, list2)\n"
">>> pairs = sorted(pairs)\n"
">>> pairs\n"
"[(\"I'm\", 'else'), ('by', 'sort'), ('sorting', 'to'), ('what', "
"'something')]\n"
">>> result = [x[1] for x in pairs]\n"
">>> result\n"
"['else', 'sort', 'to', 'something']"

msgid "Objects"
msgstr "Obiekty"

msgid "What is a class?"
msgstr "Co to jest klasa?"

msgid ""
"A class is the particular object type created by executing a class "
"statement. Class objects are used as templates to create instance objects, "
"which embody both the data (attributes) and code (methods) specific to a "
"datatype."
msgstr ""

msgid ""
"A class can be based on one or more other classes, called its base "
"class(es). It then inherits the attributes and methods of its base classes. "
"This allows an object model to be successively refined by inheritance.  You "
"might have a generic ``Mailbox`` class that provides basic accessor methods "
"for a mailbox, and subclasses such as ``MboxMailbox``, ``MaildirMailbox``, "
"``OutlookMailbox`` that handle various specific mailbox formats."
msgstr ""

msgid "What is a method?"
msgstr "Co to jest metoda?"

msgid ""
"A method is a function on some object ``x`` that you normally call as ``x."
"name(arguments...)``.  Methods are defined as functions inside the class "
"definition::"
msgstr ""

msgid ""
"class C:\n"
"    def meth(self, arg):\n"
"        return arg * 2 + self.attribute"
msgstr ""

msgid "What is self?"
msgstr "Co znaczy self?"

msgid ""
"Self is merely a conventional name for the first argument of a method.  A "
"method defined as ``meth(self, a, b, c)`` should be called as ``x.meth(a, b, "
"c)`` for some instance ``x`` of the class in which the definition occurs; "
"the called method will think it is called as ``meth(x, a, b, c)``."
msgstr ""

msgid "See also :ref:`why-self`."
msgstr ""

msgid ""
"How do I check if an object is an instance of a given class or of a subclass "
"of it?"
msgstr ""

msgid ""
"Use the built-in function :func:`isinstance(obj, cls) <isinstance>`.  You "
"can check if an object is an instance of any of a number of classes by "
"providing a tuple instead of a single class, e.g. ``isinstance(obj, (class1, "
"class2, ...))``, and can also check whether an object is one of Python's "
"built-in types, e.g. ``isinstance(obj, str)`` or ``isinstance(obj, (int, "
"float, complex))``."
msgstr ""

msgid ""
"Note that :func:`isinstance` also checks for virtual inheritance from an :"
"term:`abstract base class`.  So, the test will return ``True`` for a "
"registered class even if hasn't directly or indirectly inherited from it.  "
"To test for \"true inheritance\", scan the :term:`MRO` of the class:"
msgstr ""

msgid ""
"from collections.abc import Mapping\n"
"\n"
"class P:\n"
"     pass\n"
"\n"
"class C(P):\n"
"    pass\n"
"\n"
"Mapping.register(P)"
msgstr ""

msgid ""
">>> c = C()\n"
">>> isinstance(c, C)        # direct\n"
"True\n"
">>> isinstance(c, P)        # indirect\n"
"True\n"
">>> isinstance(c, Mapping)  # virtual\n"
"True\n"
"\n"
"# Actual inheritance chain\n"
">>> type(c).__mro__\n"
"(<class 'C'>, <class 'P'>, <class 'object'>)\n"
"\n"
"# Test for \"true inheritance\"\n"
">>> Mapping in type(c).__mro__\n"
"False"
msgstr ""

msgid ""
"Note that most programs do not use :func:`isinstance` on user-defined "
"classes very often.  If you are developing the classes yourself, a more "
"proper object-oriented style is to define methods on the classes that "
"encapsulate a particular behaviour, instead of checking the object's class "
"and doing a different thing based on what class it is.  For example, if you "
"have a function that does something::"
msgstr ""

msgid ""
"def search(obj):\n"
"    if isinstance(obj, Mailbox):\n"
"        ...  # code to search a mailbox\n"
"    elif isinstance(obj, Document):\n"
"        ...  # code to search a document\n"
"    elif ..."
msgstr ""

msgid ""
"A better approach is to define a ``search()`` method on all the classes and "
"just call it::"
msgstr ""

msgid ""
"class Mailbox:\n"
"    def search(self):\n"
"        ...  # code to search a mailbox\n"
"\n"
"class Document:\n"
"    def search(self):\n"
"        ...  # code to search a document\n"
"\n"
"obj.search()"
msgstr ""

msgid "What is delegation?"
msgstr ""

msgid ""
"Delegation is an object oriented technique (also called a design pattern). "
"Let's say you have an object ``x`` and want to change the behaviour of just "
"one of its methods.  You can create a new class that provides a new "
"implementation of the method you're interested in changing and delegates all "
"other methods to the corresponding method of ``x``."
msgstr ""

msgid ""
"Python programmers can easily implement delegation.  For example, the "
"following class implements a class that behaves like a file but converts all "
"written data to uppercase::"
msgstr ""

msgid ""
"class UpperOut:\n"
"\n"
"    def __init__(self, outfile):\n"
"        self._outfile = outfile\n"
"\n"
"    def write(self, s):\n"
"        self._outfile.write(s.upper())\n"
"\n"
"    def __getattr__(self, name):\n"
"        return getattr(self._outfile, name)"
msgstr ""

msgid ""
"Here the ``UpperOut`` class redefines the ``write()`` method to convert the "
"argument string to uppercase before calling the underlying ``self._outfile."
"write()`` method.  All other methods are delegated to the underlying ``self."
"_outfile`` object.  The delegation is accomplished via the :meth:`~object."
"__getattr__` method; consult :ref:`the language reference <attribute-"
"access>` for more information about controlling attribute access."
msgstr ""

msgid ""
"Note that for more general cases delegation can get trickier. When "
"attributes must be set as well as retrieved, the class must define a :meth:"
"`~object.__setattr__` method too, and it must do so carefully.  The basic "
"implementation of :meth:`!__setattr__` is roughly equivalent to the "
"following::"
msgstr ""

msgid ""
"class X:\n"
"    ...\n"
"    def __setattr__(self, name, value):\n"
"        self.__dict__[name] = value\n"
"    ..."
msgstr ""

msgid ""
"Many :meth:`~object.__setattr__` implementations call :meth:`!object."
"__setattr__` to set an attribute on self without causing infinite recursion::"
msgstr ""

msgid ""
"class X:\n"
"    def __setattr__(self, name, value):\n"
"        # Custom logic here...\n"
"        object.__setattr__(self, name, value)"
msgstr ""

msgid ""
"Alternatively, it is possible to set attributes by inserting entries into :"
"attr:`self.__dict__ <object.__dict__>` directly."
msgstr ""

msgid ""
"How do I call a method defined in a base class from a derived class that "
"extends it?"
msgstr ""

msgid "Use the built-in :func:`super` function::"
msgstr ""

msgid ""
"class Derived(Base):\n"
"    def meth(self):\n"
"        super().meth()  # calls Base.meth"
msgstr ""

msgid ""
"In the example, :func:`super` will automatically determine the instance from "
"which it was called (the ``self`` value), look up the :term:`method "
"resolution order` (MRO) with ``type(self).__mro__``, and return the next in "
"line after ``Derived`` in the MRO: ``Base``."
msgstr ""

msgid "How can I organize my code to make it easier to change the base class?"
msgstr ""

msgid ""
"You could assign the base class to an alias and derive from the alias.  Then "
"all you have to change is the value assigned to the alias.  Incidentally, "
"this trick is also handy if you want to decide dynamically (e.g. depending "
"on availability of resources) which base class to use.  Example::"
msgstr ""

msgid ""
"class Base:\n"
"    ...\n"
"\n"
"BaseAlias = Base\n"
"\n"
"class Derived(BaseAlias):\n"
"    ..."
msgstr ""

msgid "How do I create static class data and static class methods?"
msgstr ""

msgid ""
"Both static data and static methods (in the sense of C++ or Java) are "
"supported in Python."
msgstr ""

msgid ""
"For static data, simply define a class attribute.  To assign a new value to "
"the attribute, you have to explicitly use the class name in the assignment::"
msgstr ""

msgid ""
"class C:\n"
"    count = 0   # number of times C.__init__ called\n"
"\n"
"    def __init__(self):\n"
"        C.count = C.count + 1\n"
"\n"
"    def getcount(self):\n"
"        return C.count  # or return self.count"
msgstr ""

msgid ""
"``c.count`` also refers to ``C.count`` for any ``c`` such that "
"``isinstance(c, C)`` holds, unless overridden by ``c`` itself or by some "
"class on the base-class search path from ``c.__class__`` back to ``C``."
msgstr ""

msgid ""
"Caution: within a method of C, an assignment like ``self.count = 42`` "
"creates a new and unrelated instance named \"count\" in ``self``'s own "
"dict.  Rebinding of a class-static data name must always specify the class "
"whether inside a method or not::"
msgstr ""

msgid "C.count = 314"
msgstr ""

msgid "Static methods are possible::"
msgstr ""

msgid ""
"class C:\n"
"    @staticmethod\n"
"    def static(arg1, arg2, arg3):\n"
"        # No 'self' parameter!\n"
"        ..."
msgstr ""

msgid ""
"However, a far more straightforward way to get the effect of a static method "
"is via a simple module-level function::"
msgstr ""

msgid ""
"def getcount():\n"
"    return C.count"
msgstr ""

msgid ""
"If your code is structured so as to define one class (or tightly related "
"class hierarchy) per module, this supplies the desired encapsulation."
msgstr ""

msgid "How can I overload constructors (or methods) in Python?"
msgstr ""

msgid ""
"This answer actually applies to all methods, but the question usually comes "
"up first in the context of constructors."
msgstr ""

msgid "In C++ you'd write"
msgstr ""

msgid ""
"class C {\n"
"    C() { cout << \"No arguments\\n\"; }\n"
"    C(int i) { cout << \"Argument is \" << i << \"\\n\"; }\n"
"}"
msgstr ""

msgid ""
"In Python you have to write a single constructor that catches all cases "
"using default arguments.  For example::"
msgstr ""

msgid ""
"class C:\n"
"    def __init__(self, i=None):\n"
"        if i is None:\n"
"            print(\"No arguments\")\n"
"        else:\n"
"            print(\"Argument is\", i)"
msgstr ""

msgid "This is not entirely equivalent, but close enough in practice."
msgstr ""

msgid "You could also try a variable-length argument list, e.g. ::"
msgstr ""

msgid ""
"def __init__(self, *args):\n"
"    ..."
msgstr ""

msgid "The same approach works for all method definitions."
msgstr ""

msgid "I try to use __spam and I get an error about _SomeClassName__spam."
msgstr ""

msgid ""
"Variable names with double leading underscores are \"mangled\" to provide a "
"simple but effective way to define class private variables.  Any identifier "
"of the form ``__spam`` (at least two leading underscores, at most one "
"trailing underscore) is textually replaced with ``_classname__spam``, where "
"``classname`` is the current class name with any leading underscores "
"stripped."
msgstr ""

msgid ""
"The identifier can be used unchanged within the class, but to access it "
"outside the class, the mangled name must be used:"
msgstr ""

msgid ""
"class A:\n"
"    def __one(self):\n"
"        return 1\n"
"    def two(self):\n"
"        return 2 * self.__one()\n"
"\n"
"class B(A):\n"
"    def three(self):\n"
"        return 3 * self._A__one()\n"
"\n"
"four = 4 * A()._A__one()"
msgstr ""

msgid ""
"In particular, this does not guarantee privacy since an outside user can "
"still deliberately access the private attribute; many Python programmers "
"never bother to use private variable names at all."
msgstr ""

msgid ""
"The :ref:`private name mangling specifications <private-name-mangling>` for "
"details and special cases."
msgstr ""
"Szczegółowe informacje i przypadki specjalne znajdują się w specyfikacji :"
"ref:`private name mangling <private-name-mangling>`."

msgid "My class defines __del__ but it is not called when I delete the object."
msgstr ""

msgid "There are several possible reasons for this."
msgstr ""

msgid ""
"The :keyword:`del` statement does not necessarily call :meth:`~object."
"__del__` -- it simply decrements the object's reference count, and if this "
"reaches zero :meth:`!__del__` is called."
msgstr ""

msgid ""
"If your data structures contain circular links (e.g. a tree where each child "
"has a parent reference and each parent has a list of children) the reference "
"counts will never go back to zero.  Once in a while Python runs an algorithm "
"to detect such cycles, but the garbage collector might run some time after "
"the last reference to your data structure vanishes, so your :meth:`!__del__` "
"method may be called at an inconvenient and random time. This is "
"inconvenient if you're trying to reproduce a problem. Worse, the order in "
"which object's :meth:`!__del__` methods are executed is arbitrary.  You can "
"run :func:`gc.collect` to force a collection, but there *are* pathological "
"cases where objects will never be collected."
msgstr ""

msgid ""
"Despite the cycle collector, it's still a good idea to define an explicit "
"``close()`` method on objects to be called whenever you're done with them.  "
"The ``close()`` method can then remove attributes that refer to subobjects.  "
"Don't call :meth:`!__del__` directly -- :meth:`!__del__` should call "
"``close()`` and ``close()`` should make sure that it can be called more than "
"once for the same object."
msgstr ""

msgid ""
"Another way to avoid cyclical references is to use the :mod:`weakref` "
"module, which allows you to point to objects without incrementing their "
"reference count. Tree data structures, for instance, should use weak "
"references for their parent and sibling references (if they need them!)."
msgstr ""

msgid ""
"Finally, if your :meth:`!__del__` method raises an exception, a warning "
"message is printed to :data:`sys.stderr`."
msgstr ""

msgid "How do I get a list of all instances of a given class?"
msgstr ""

msgid ""
"Python does not keep track of all instances of a class (or of a built-in "
"type). You can program the class's constructor to keep track of all "
"instances by keeping a list of weak references to each instance."
msgstr ""

msgid "Why does the result of ``id()`` appear to be not unique?"
msgstr ""

msgid ""
"The :func:`id` builtin returns an integer that is guaranteed to be unique "
"during the lifetime of the object.  Since in CPython, this is the object's "
"memory address, it happens frequently that after an object is deleted from "
"memory, the next freshly created object is allocated at the same position in "
"memory.  This is illustrated by this example:"
msgstr ""

msgid ""
"The two ids belong to different integer objects that are created before, and "
"deleted immediately after execution of the ``id()`` call.  To be sure that "
"objects whose id you want to examine are still alive, create another "
"reference to the object:"
msgstr ""

msgid "When can I rely on identity tests with the *is* operator?"
msgstr ""

msgid ""
"The ``is`` operator tests for object identity.  The test ``a is b`` is "
"equivalent to ``id(a) == id(b)``."
msgstr ""

msgid ""
"The most important property of an identity test is that an object is always "
"identical to itself, ``a is a`` always returns ``True``.  Identity tests are "
"usually faster than equality tests.  And unlike equality tests, identity "
"tests are guaranteed to return a boolean ``True`` or ``False``."
msgstr ""

msgid ""
"However, identity tests can *only* be substituted for equality tests when "
"object identity is assured.  Generally, there are three circumstances where "
"identity is guaranteed:"
msgstr ""

msgid ""
"Assignments create new names but do not change object identity.  After the "
"assignment ``new = old``, it is guaranteed that ``new is old``."
msgstr ""

msgid ""
"Putting an object in a container that stores object references does not "
"change object identity.  After the list assignment ``s[0] = x``, it is "
"guaranteed that ``s[0] is x``."
msgstr ""

msgid ""
"If an object is a singleton, it means that only one instance of that object "
"can exist.  After the assignments ``a = None`` and ``b = None``, it is "
"guaranteed that ``a is b`` because ``None`` is a singleton."
msgstr ""

msgid ""
"In most other circumstances, identity tests are inadvisable and equality "
"tests are preferred.  In particular, identity tests should not be used to "
"check constants such as :class:`int` and :class:`str` which aren't "
"guaranteed to be singletons::"
msgstr ""

msgid ""
">>> a = 1000\n"
">>> b = 500\n"
">>> c = b + 500\n"
">>> a is c\n"
"False\n"
"\n"
">>> a = 'Python'\n"
">>> b = 'Py'\n"
">>> c = b + 'thon'\n"
">>> a is c\n"
"False"
msgstr ""
">>> a = 1000\n"
">>> b = 500\n"
">>> c = b + 500\n"
">>> a is c\n"
"False\n"
"\n"
">>> a = 'Python'\n"
">>> b = 'Py'\n"
">>> c = b + 'thon'\n"
">>> a is c\n"
"False"

msgid "Likewise, new instances of mutable containers are never identical::"
msgstr ""

msgid ""
">>> a = []\n"
">>> b = []\n"
">>> a is b\n"
"False"
msgstr ""
">>> a = []\n"
">>> b = []\n"
">>> a is b\n"
"False"

msgid ""
"In the standard library code, you will see several common patterns for "
"correctly using identity tests:"
msgstr ""

msgid ""
"As recommended by :pep:`8`, an identity test is the preferred way to check "
"for ``None``.  This reads like plain English in code and avoids confusion "
"with other objects that may have boolean values that evaluate to false."
msgstr ""

msgid ""
"Detecting optional arguments can be tricky when ``None`` is a valid input "
"value.  In those situations, you can create a singleton sentinel object "
"guaranteed to be distinct from other objects.  For example, here is how to "
"implement a method that behaves like :meth:`dict.pop`:"
msgstr ""

msgid ""
"_sentinel = object()\n"
"\n"
"def pop(self, key, default=_sentinel):\n"
"    if key in self:\n"
"        value = self[key]\n"
"        del self[key]\n"
"        return value\n"
"    if default is _sentinel:\n"
"        raise KeyError(key)\n"
"    return default"
msgstr ""

msgid ""
"Container implementations sometimes need to augment equality tests with "
"identity tests.  This prevents the code from being confused by objects such "
"as ``float('NaN')`` that are not equal to themselves."
msgstr ""

msgid ""
"For example, here is the implementation of :meth:`!collections.abc.Sequence."
"__contains__`::"
msgstr ""

msgid ""
"def __contains__(self, value):\n"
"    for v in self:\n"
"        if v is value or v == value:\n"
"            return True\n"
"    return False"
msgstr ""

msgid ""
"How can a subclass control what data is stored in an immutable instance?"
msgstr ""

msgid ""
"When subclassing an immutable type, override the :meth:`~object.__new__` "
"method instead of the :meth:`~object.__init__` method.  The latter only runs "
"*after* an instance is created, which is too late to alter data in an "
"immutable instance."
msgstr ""

msgid ""
"All of these immutable classes have a different signature than their parent "
"class:"
msgstr ""

msgid ""
"from datetime import date\n"
"\n"
"class FirstOfMonthDate(date):\n"
"    \"Always choose the first day of the month\"\n"
"    def __new__(cls, year, month, day):\n"
"        return super().__new__(cls, year, month, 1)\n"
"\n"
"class NamedInt(int):\n"
"    \"Allow text names for some numbers\"\n"
"    xlat = {'zero': 0, 'one': 1, 'ten': 10}\n"
"    def __new__(cls, value):\n"
"        value = cls.xlat.get(value, value)\n"
"        return super().__new__(cls, value)\n"
"\n"
"class TitleStr(str):\n"
"    \"Convert str to name suitable for a URL path\"\n"
"    def __new__(cls, s):\n"
"        s = s.lower().replace(' ', '-')\n"
"        s = ''.join([c for c in s if c.isalnum() or c == '-'])\n"
"        return super().__new__(cls, s)"
msgstr ""

msgid "The classes can be used like this:"
msgstr ""

msgid ""
">>> FirstOfMonthDate(2012, 2, 14)\n"
"FirstOfMonthDate(2012, 2, 1)\n"
">>> NamedInt('ten')\n"
"10\n"
">>> NamedInt(20)\n"
"20\n"
">>> TitleStr('Blog: Why Python Rocks')\n"
"'blog-why-python-rocks'"
msgstr ""

msgid "How do I cache method calls?"
msgstr ""

msgid ""
"The two principal tools for caching methods are :func:`functools."
"cached_property` and :func:`functools.lru_cache`.  The former stores results "
"at the instance level and the latter at the class level."
msgstr ""

msgid ""
"The *cached_property* approach only works with methods that do not take any "
"arguments.  It does not create a reference to the instance.  The cached "
"method result will be kept only as long as the instance is alive."
msgstr ""

msgid ""
"The advantage is that when an instance is no longer used, the cached method "
"result will be released right away.  The disadvantage is that if instances "
"accumulate, so too will the accumulated method results.  They can grow "
"without bound."
msgstr ""

msgid ""
"The *lru_cache* approach works with methods that have :term:`hashable` "
"arguments.  It creates a reference to the instance unless special efforts "
"are made to pass in weak references."
msgstr ""

msgid ""
"The advantage of the least recently used algorithm is that the cache is "
"bounded by the specified *maxsize*.  The disadvantage is that instances are "
"kept alive until they age out of the cache or until the cache is cleared."
msgstr ""

msgid "This example shows the various techniques::"
msgstr ""

msgid ""
"class Weather:\n"
"    \"Lookup weather information on a government website\"\n"
"\n"
"    def __init__(self, station_id):\n"
"        self._station_id = station_id\n"
"        # The _station_id is private and immutable\n"
"\n"
"    def current_temperature(self):\n"
"        \"Latest hourly observation\"\n"
"        # Do not cache this because old results\n"
"        # can be out of date.\n"
"\n"
"    @cached_property\n"
"    def location(self):\n"
"        \"Return the longitude/latitude coordinates of the station\"\n"
"        # Result only depends on the station_id\n"
"\n"
"    @lru_cache(maxsize=20)\n"
"    def historic_rainfall(self, date, units='mm'):\n"
"        \"Rainfall on a given date\"\n"
"        # Depends on the station_id, date, and units."
msgstr ""

msgid ""
"The above example assumes that the *station_id* never changes.  If the "
"relevant instance attributes are mutable, the *cached_property* approach "
"can't be made to work because it cannot detect changes to the attributes."
msgstr ""

msgid ""
"To make the *lru_cache* approach work when the *station_id* is mutable, the "
"class needs to define the :meth:`~object.__eq__` and :meth:`~object."
"__hash__` methods so that the cache can detect relevant attribute updates::"
msgstr ""

msgid ""
"class Weather:\n"
"    \"Example with a mutable station identifier\"\n"
"\n"
"    def __init__(self, station_id):\n"
"        self.station_id = station_id\n"
"\n"
"    def change_station(self, station_id):\n"
"        self.station_id = station_id\n"
"\n"
"    def __eq__(self, other):\n"
"        return self.station_id == other.station_id\n"
"\n"
"    def __hash__(self):\n"
"        return hash(self.station_id)\n"
"\n"
"    @lru_cache(maxsize=20)\n"
"    def historic_rainfall(self, date, units='cm'):\n"
"        'Rainfall on a given date'\n"
"        # Depends on the station_id, date, and units."
msgstr ""

msgid "Modules"
msgstr "Moduły"

msgid "How do I create a .pyc file?"
msgstr ""

msgid ""
"When a module is imported for the first time (or when the source file has "
"changed since the current compiled file was created) a ``.pyc`` file "
"containing the compiled code should be created in a ``__pycache__`` "
"subdirectory of the directory containing the ``.py`` file.  The ``.pyc`` "
"file will have a filename that starts with the same name as the ``.py`` "
"file, and ends with ``.pyc``, with a middle component that depends on the "
"particular ``python`` binary that created it.  (See :pep:`3147` for details.)"
msgstr ""

msgid ""
"One reason that a ``.pyc`` file may not be created is a permissions problem "
"with the directory containing the source file, meaning that the "
"``__pycache__`` subdirectory cannot be created. This can happen, for "
"example, if you develop as one user but run as another, such as if you are "
"testing with a web server."
msgstr ""

msgid ""
"Unless the :envvar:`PYTHONDONTWRITEBYTECODE` environment variable is set, "
"creation of a .pyc file is automatic if you're importing a module and Python "
"has the ability (permissions, free space, etc...) to create a "
"``__pycache__`` subdirectory and write the compiled module to that "
"subdirectory."
msgstr ""

msgid ""
"Running Python on a top level script is not considered an import and no ``."
"pyc`` will be created.  For example, if you have a top-level module ``foo."
"py`` that imports another module ``xyz.py``, when you run ``foo`` (by typing "
"``python foo.py`` as a shell command), a ``.pyc`` will be created for "
"``xyz`` because ``xyz`` is imported, but no ``.pyc`` file will be created "
"for ``foo`` since ``foo.py`` isn't being imported."
msgstr ""

msgid ""
"If you need to create a ``.pyc`` file for ``foo`` -- that is, to create a ``."
"pyc`` file for a module that is not imported -- you can, using the :mod:"
"`py_compile` and :mod:`compileall` modules."
msgstr ""

msgid ""
"The :mod:`py_compile` module can manually compile any module.  One way is to "
"use the ``compile()`` function in that module interactively::"
msgstr ""

msgid ""
">>> import py_compile\n"
">>> py_compile.compile('foo.py')"
msgstr ""
">>> import py_compile\n"
">>> py_compile.compile('foo.py')"

msgid ""
"This will write the ``.pyc`` to a ``__pycache__`` subdirectory in the same "
"location as ``foo.py`` (or you can override that with the optional parameter "
"``cfile``)."
msgstr ""

msgid ""
"You can also automatically compile all files in a directory or directories "
"using the :mod:`compileall` module.  You can do it from the shell prompt by "
"running ``compileall.py`` and providing the path of a directory containing "
"Python files to compile::"
msgstr ""

msgid "python -m compileall ."
msgstr ""

msgid "How do I find the current module name?"
msgstr ""

msgid ""
"A module can find out its own module name by looking at the predefined "
"global variable ``__name__``.  If this has the value ``'__main__'``, the "
"program is running as a script.  Many modules that are usually used by "
"importing them also provide a command-line interface or a self-test, and "
"only execute this code after checking ``__name__``::"
msgstr ""

msgid ""
"def main():\n"
"    print('Running test...')\n"
"    ...\n"
"\n"
"if __name__ == '__main__':\n"
"    main()"
msgstr ""

msgid "How can I have modules that mutually import each other?"
msgstr ""

msgid "Suppose you have the following modules:"
msgstr ""

msgid ":file:`foo.py`::"
msgstr ":file:`foo.py`::"

msgid ""
"from bar import bar_var\n"
"foo_var = 1"
msgstr ""

msgid ":file:`bar.py`::"
msgstr ":file:`bar.py`::"

msgid ""
"from foo import foo_var\n"
"bar_var = 2"
msgstr ""

msgid "The problem is that the interpreter will perform the following steps:"
msgstr ""

msgid "main imports ``foo``"
msgstr ""

msgid "Empty globals for ``foo`` are created"
msgstr ""

msgid "``foo`` is compiled and starts executing"
msgstr ""

msgid "``foo`` imports ``bar``"
msgstr ""

msgid "Empty globals for ``bar`` are created"
msgstr ""

msgid "``bar`` is compiled and starts executing"
msgstr ""

msgid ""
"``bar`` imports ``foo`` (which is a no-op since there already is a module "
"named ``foo``)"
msgstr ""

msgid ""
"The import mechanism tries to read ``foo_var`` from ``foo`` globals, to set "
"``bar.foo_var = foo.foo_var``"
msgstr ""

msgid ""
"The last step fails, because Python isn't done with interpreting ``foo`` yet "
"and the global symbol dictionary for ``foo`` is still empty."
msgstr ""

msgid ""
"The same thing happens when you use ``import foo``, and then try to access "
"``foo.foo_var`` in global code."
msgstr ""

msgid "There are (at least) three possible workarounds for this problem."
msgstr ""

msgid ""
"Guido van Rossum recommends avoiding all uses of ``from <module> import ..."
"``, and placing all code inside functions.  Initializations of global "
"variables and class variables should use constants or built-in functions "
"only.  This means everything from an imported module is referenced as "
"``<module>.<name>``."
msgstr ""

msgid ""
"Jim Roskind suggests performing steps in the following order in each module:"
msgstr ""

msgid ""
"exports (globals, functions, and classes that don't need imported base "
"classes)"
msgstr ""

msgid "``import`` statements"
msgstr ""

msgid ""
"active code (including globals that are initialized from imported values)."
msgstr ""

msgid ""
"Van Rossum doesn't like this approach much because the imports appear in a "
"strange place, but it does work."
msgstr ""

msgid ""
"Matthias Urlichs recommends restructuring your code so that the recursive "
"import is not necessary in the first place."
msgstr ""

msgid "These solutions are not mutually exclusive."
msgstr ""

msgid "__import__('x.y.z') returns <module 'x'>; how do I get z?"
msgstr ""

msgid ""
"Consider using the convenience function :func:`~importlib.import_module` "
"from :mod:`importlib` instead::"
msgstr ""

msgid "z = importlib.import_module('x.y.z')"
msgstr ""

msgid ""
"When I edit an imported module and reimport it, the changes don't show up.  "
"Why does this happen?"
msgstr ""

msgid ""
"For reasons of efficiency as well as consistency, Python only reads the "
"module file on the first time a module is imported.  If it didn't, in a "
"program consisting of many modules where each one imports the same basic "
"module, the basic module would be parsed and re-parsed many times.  To force "
"re-reading of a changed module, do this::"
msgstr ""

msgid ""
"import importlib\n"
"import modname\n"
"importlib.reload(modname)"
msgstr ""

msgid ""
"Warning: this technique is not 100% fool-proof.  In particular, modules "
"containing statements like ::"
msgstr ""

msgid "from modname import some_objects"
msgstr ""

msgid ""
"will continue to work with the old version of the imported objects.  If the "
"module contains class definitions, existing class instances will *not* be "
"updated to use the new class definition.  This can result in the following "
"paradoxical behaviour::"
msgstr ""

msgid ""
">>> import importlib\n"
">>> import cls\n"
">>> c = cls.C()                # Create an instance of C\n"
">>> importlib.reload(cls)\n"
"<module 'cls' from 'cls.py'>\n"
">>> isinstance(c, cls.C)       # isinstance is false?!?\n"
"False"
msgstr ""

msgid ""
"The nature of the problem is made clear if you print out the \"identity\" of "
"the class objects::"
msgstr ""

msgid ""
">>> hex(id(c.__class__))\n"
"'0x7352a0'\n"
">>> hex(id(cls.C))\n"
"'0x4198d0'"
msgstr ""
">>> hex(id(c.__class__))\n"
"'0x7352a0'\n"
">>> hex(id(cls.C))\n"
"'0x4198d0'"

msgid "argument"
msgstr "argument"

msgid "difference from parameter"
msgstr ""

msgid "parameter"
msgstr ""

msgid "difference from argument"
msgstr ""