frequently_used_terms.md

Python: Frequently Used Terms

Class

A "template" or constructor for objects, which can combine information and behavior. Used in Object-Oriented Programming. Creating a new class creates a new type of object, allowing new instances of that type to be made. To create a class, use the keyword class:

>>> class MyClass:      # here we create the class
>>>   x = 5

>>> p1 = MyClass()      # here we create the object (see below)
>>> print(p1.x)
  5

Object

An encapsulation of variables and functions. In Python, everything is an object: strings, lists, functions--even modules. Typically, an object is a member or an "instance" of a class: it takes variables and functions from that class. It Accepts arguments (called parameters), and possible return objects.

>>> p1 = MyClass()    # p1 is an object
>>> print(p1.x)
  5

Variable

A reserved memory location to store values. When you create a variable you reserve some space in memory.

Function

A callable object. A function is a block of code which only runs when it is called. You can pass data, known as parameters, into a function.

Method

A function that belongs to an object. E.g. list objects have methods called .append, .insert, .remove, .sort, and so on.

Expression

Combinations of values and operators that always evaluate down to a single value. E.g. the code snippet 2 * 2

Statement

An instruction that does not evaluate down to a value. E.g. the code snippet while True:

Parameter

These are defined by the names that appear in a function definition. E.g. def calc_sum(a,b):

Argument

The values actually passed to a function when calling it. E.g. calc_sum(2,5)

Recursive function

Function that, somewhere in its body, calls itself.