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# -*- coding: utf-8 -*-
"""Implementation of execution-related magic functions."""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import ast
import bdb
import builtins as builtin_mod
import gc
import itertools
import os
import shlex
import sys
import time
import timeit
import math
from pdb import Restart
# cProfile was added in Python2.5
import cProfile as profile
import pstats
except ImportError:
# profile isn't bundled by default in Debian for license reasons
import profile, pstats
except ImportError:
profile = pstats = None
from IPython.core import oinspect
from IPython.core import magic_arguments
from IPython.core import page
from IPython.core.error import UsageError
from IPython.core.macro import Macro
from IPython.core.magic import (Magics, magics_class, line_magic, cell_magic,
line_cell_magic, on_off, needs_local_scope)
from IPython.testing.skipdoctest import skip_doctest
from IPython.utils.contexts import preserve_keys
from IPython.utils.capture import capture_output
from IPython.utils.ipstruct import Struct
from IPython.utils.module_paths import find_mod
from IPython.utils.path import get_py_filename, shellglob
from IPython.utils.timing import clock, clock2
from warnings import warn
from logging import error
from io import StringIO
# Magic implementation classes
class TimeitResult(object):
Object returned by the timeit magic with info about the run.
Contains the following attributes :
loops: (int) number of loops done per measurement
repeat: (int) number of times the measurement has been repeated
best: (float) best execution time / number
all_runs: (list of float) execution time of each run (in s)
compile_time: (float) time of statement compilation (s)
def __init__(self, loops, repeat, best, worst, all_runs, compile_time, precision):
self.loops = loops
self.repeat = repeat = best
self.worst = worst
self.all_runs = all_runs
self.compile_time = compile_time
self._precision = precision
self.timings = [ dt / self.loops for dt in all_runs]
def average(self):
return math.fsum(self.timings) / len(self.timings)
def stdev(self):
mean = self.average
return (math.fsum([(x - mean) ** 2 for x in self.timings]) / len(self.timings)) ** 0.5
def __str__(self):
pm = '+-'
if hasattr(sys.stdout, 'encoding') and sys.stdout.encoding:
pm = u'\xb1'
return (
u"{mean} {pm} {std} per loop (mean {pm} std. dev. of {runs} run{run_plural}, {loops} loop{loop_plural} each)"
pm = pm,
runs = self.repeat,
loops = self.loops,
loop_plural = "" if self.loops == 1 else "s",
run_plural = "" if self.repeat == 1 else "s",
mean = _format_time(self.average, self._precision),
std = _format_time(self.stdev, self._precision))
def _repr_pretty_(self, p , cycle):
unic = self.__str__()
p.text(u'<TimeitResult : '+unic+u'>')
class TimeitTemplateFiller(ast.NodeTransformer):
"""Fill in the AST template for timing execution.
This is quite closely tied to the template definition, which is in
def __init__(self, ast_setup, ast_stmt):
self.ast_setup = ast_setup
self.ast_stmt = ast_stmt
def visit_FunctionDef(self, node):
"Fill in the setup statement"
if == "inner":
node.body[:1] = self.ast_setup.body
return node
def visit_For(self, node):
"Fill in the statement to be timed"
if getattr(getattr(node.body[0], 'value', None), 'id', None) == 'stmt':
node.body = self.ast_stmt.body
return node
class Timer(timeit.Timer):
"""Timer class that explicitly uses self.inner
which is an undocumented implementation detail of CPython,
not shared by PyPy.
# Timer.timeit copied from CPython 3.4.2
def timeit(self, number=timeit.default_number):
"""Time 'number' executions of the main statement.
To be precise, this executes the setup statement once, and
then returns the time it takes to execute the main statement
a number of times, as a float measured in seconds. The
argument is the number of times through the loop, defaulting
to one million. The main statement, the setup statement and
the timer function to be used are passed to the constructor.
it = itertools.repeat(None, number)
gcold = gc.isenabled()
timing = self.inner(it, self.timer)
if gcold:
return timing
class ExecutionMagics(Magics):
"""Magics related to code execution, debugging, profiling, etc.
def __init__(self, shell):
super(ExecutionMagics, self).__init__(shell)
if profile is None:
self.prun = self.profile_missing_notice
# Default execution function used to actually run user code.
self.default_runner = None
def profile_missing_notice(self, *args, **kwargs):
The profile module could not be found. It has been removed from the standard
python packages because of its non-free license. To use profiling, install the
python-profiler package from non-free.""")
def prun(self, parameter_s='', cell=None):
"""Run a statement through the python code profiler.
Usage, in line mode:
%prun [options] statement
Usage, in cell mode:
%%prun [options] [statement]
In cell mode, the additional code lines are appended to the (possibly
empty) statement in the first line. Cell mode allows you to easily
profile multiline blocks without having to put them in a separate
The given statement (which doesn't require quote marks) is run via the
python profiler in a manner similar to the function.
Namespaces are internally managed to work correctly;
cannot be used in IPython because it makes certain assumptions about
namespaces which do not hold under IPython.
-l <limit>
you can place restrictions on what or how much of the
profile gets printed. The limit value can be:
* A string: only information for function names containing this string
is printed.
* An integer: only these many lines are printed.
* A float (between 0 and 1): this fraction of the report is printed
(for example, use a limit of 0.4 to see the topmost 40% only).
You can combine several limits with repeated use of the option. For
example, ``-l __init__ -l 5`` will print only the topmost 5 lines of
information about class constructors.
return the pstats.Stats object generated by the profiling. This
object has all the information about the profile in it, and you can
later use it for further analysis or in other functions.
-s <key>
sort profile by given key. You can provide more than one key
by using the option several times: '-s key1 -s key2 -s key3...'. The
default sorting key is 'time'.
The following is copied verbatim from the profile documentation
referenced below:
When more than one key is provided, additional keys are used as
secondary criteria when the there is equality in all keys selected
before them.
Abbreviations can be used for any key names, as long as the
abbreviation is unambiguous. The following are the keys currently
============ =====================
Valid Arg Meaning
============ =====================
"calls" call count
"cumulative" cumulative time
"file" file name
"module" file name
"pcalls" primitive call count
"line" line number
"name" function name
"nfl" name/file/line
"stdname" standard name
"time" internal time
============ =====================
Note that all sorts on statistics are in descending order (placing
most time consuming items first), where as name, file, and line number
searches are in ascending order (i.e., alphabetical). The subtle
distinction between "nfl" and "stdname" is that the standard name is a
sort of the name as printed, which means that the embedded line
numbers get compared in an odd way. For example, lines 3, 20, and 40
would (if the file names were the same) appear in the string order
"20" "3" and "40". In contrast, "nfl" does a numeric compare of the
line numbers. In fact, sort_stats("nfl") is the same as
sort_stats("name", "file", "line").
-T <filename>
save profile results as shown on screen to a text
file. The profile is still shown on screen.
-D <filename>
save (via dump_stats) profile statistics to given
filename. This data is in a format understood by the pstats module, and
is generated by a call to the dump_stats() method of profile
objects. The profile is still shown on screen.
suppress output to the pager. Best used with -T and/or -D above.
If you want to run complete programs under the profiler's control, use
``%run -p [prof_opts] [args to program]`` where prof_opts
contains profiler specific options as described here.
You can read the complete documentation for the profile module with::
In [1]: import profile;
opts, arg_str = self.parse_options(parameter_s, 'D:l:rs:T:q',
list_all=True, posix=False)
if cell is not None:
arg_str += '\n' + cell
arg_str =
return self._run_with_profiler(arg_str, opts,
def _run_with_profiler(self, code, opts, namespace):
Run `code` with profiler. Used by ``%prun`` and ``%run -p``.
code : str
Code to be executed.
opts : Struct
Options parsed by `self.parse_options`.
namespace : dict
A dictionary for Python namespace (e.g., ``).
# Fill default values for unspecified options:
opts.merge(Struct(D=[''], l=[], s=['time'], T=['']))
prof = profile.Profile()
prof = prof.runctx(code, namespace, namespace)
sys_exit = ''
except SystemExit:
sys_exit = """*** SystemExit exception caught in code being profiled."""
stats = pstats.Stats(prof).strip_dirs().sort_stats(*opts.s)
lims = opts.l
if lims:
lims = [] # rebuild lims with ints/floats/strings
for lim in opts.l:
except ValueError:
except ValueError:
# Trap output.
stdout_trap = StringIO()
stats_stream =
try: = stdout_trap
finally: = stats_stream
output = stdout_trap.getvalue()
output = output.rstrip()
if 'q' not in opts:
print(sys_exit, end=' ')
dump_file = opts.D[0]
text_file = opts.T[0]
if dump_file:
print('\n*** Profile stats marshalled to file',\
if text_file:
pfile = open(text_file,'w')
print('\n*** Profile printout saved to text file',\
if 'r' in opts:
return stats
return None
def pdb(self, parameter_s=''):
"""Control the automatic calling of the pdb interactive debugger.
Call as '%pdb on', '%pdb 1', '%pdb off' or '%pdb 0'. If called without
argument it works as a toggle.
When an exception is triggered, IPython can optionally call the
interactive pdb debugger after the traceback printout. %pdb toggles
this feature on and off.
The initial state of this feature is set in your configuration
file (the option is ``InteractiveShell.pdb``).
If you want to just activate the debugger AFTER an exception has fired,
without having to type '%pdb on' and rerunning your code, you can use
the %debug magic."""
par = parameter_s.strip().lower()
if par:
new_pdb = {'off':0,'0':0,'on':1,'1':1}[par]
except KeyError:
print ('Incorrect argument. Use on/1, off/0, '
'or nothing for a toggle.')
# toggle
new_pdb = not
# set on the shell = new_pdb
print('Automatic pdb calling has been turned',on_off(new_pdb))
@magic_arguments.argument('--breakpoint', '-b', metavar='FILE:LINE',
Set break point at LINE in FILE.
@magic_arguments.argument('statement', nargs='*',
Code to run in debugger.
You can omit this in cell magic mode.
def debug(self, line='', cell=None):
"""Activate the interactive debugger.
This magic command support two ways of activating debugger.
One is to activate debugger before executing code. This way, you
can set a break point, to step through the code from the point.
You can use this mode by giving statements to execute and optionally
a breakpoint.
The other one is to activate debugger in post-mortem mode. You can
activate this mode simply running %debug without any argument.
If an exception has just occurred, this lets you inspect its stack
frames interactively. Note that this will always work only on the last
traceback that occurred, so you must call this quickly after an
exception that you wish to inspect has fired, because if another one
occurs, it clobbers the previous one.
If you want IPython to automatically do this on every exception, see
the %pdb magic for more details.
args = magic_arguments.parse_argstring(self.debug, line)
if not (args.breakpoint or args.statement or cell):
code = "\n".join(args.statement)
if cell:
code += "\n" + cell
self._debug_exec(code, args.breakpoint)
def _debug_post_mortem(self):
def _debug_exec(self, code, breakpoint):
if breakpoint:
(filename, bp_line) = breakpoint.rsplit(':', 1)
bp_line = int(bp_line)
(filename, bp_line) = (None, None)
self._run_with_debugger(code,, filename, bp_line)
def tb(self, s):
"""Print the last traceback with the currently active exception mode.
See %xmode for changing exception reporting modes."""
def run(self, parameter_s='', runner=None,
"""Run the named file inside IPython as a program.
%run [-n -i -e -G]
[( -t [-N<N>] | -d [-b<N>] | -p [profile options] )]
( -m mod | file ) [args]
Parameters after the filename are passed as command-line arguments to
the program (put in sys.argv). Then, control returns to IPython's
This is similar to running at a system prompt ``python file args``,
but with the advantage of giving you IPython's tracebacks, and of
loading all variables into your interactive namespace for further use
(unless -p is used, see below).
The file is executed in a namespace initially consisting only of
``__name__=='__main__'`` and sys.argv constructed as indicated. It thus
sees its environment as if it were being run as a stand-alone program
(except for sharing global objects such as previously imported
modules). But after execution, the IPython interactive namespace gets
updated with all variables defined in the program (except for __name__
and sys.argv). This allows for very convenient loading of code for
interactive work, while giving each program a 'clean sheet' to run in.
Arguments are expanded using shell-like glob match. Patterns
'*', '?', '[seq]' and '[!seq]' can be used. Additionally,
tilde '~' will be expanded into user's home directory. Unlike
real shells, quotation does not suppress expansions. Use
*two* back slashes (e.g. ``\\\\*``) to suppress expansions.
To completely disable these expansions, you can use -G flag.
__name__ is NOT set to '__main__', but to the running file's name
without extension (as python does under import). This allows running
scripts and reloading the definitions in them without calling code
protected by an ``if __name__ == "__main__"`` clause.
run the file in IPython's namespace instead of an empty one. This
is useful if you are experimenting with code written in a text editor
which depends on variables defined interactively.
ignore sys.exit() calls or SystemExit exceptions in the script
being run. This is particularly useful if IPython is being used to
run unittests, which always exit with a sys.exit() call. In such
cases you are interested in the output of the test results, not in
seeing a traceback of the unittest module.
print timing information at the end of the run. IPython will give
you an estimated CPU time consumption for your script, which under
Unix uses the resource module to avoid the wraparound problems of
time.clock(). Under Unix, an estimate of time spent on system tasks
is also given (for Windows platforms this is reported as 0.0).
If -t is given, an additional ``-N<N>`` option can be given, where <N>
must be an integer indicating how many times you want the script to
run. The final timing report will include total and per run results.
For example (testing the script
In [1]: run -t uniq_stable
IPython CPU timings (estimated):
User : 0.19597 s.
System: 0.0 s.
In [2]: run -t -N5 uniq_stable
IPython CPU timings (estimated):
Total runs performed: 5
Times : Total Per run
User : 0.910862 s, 0.1821724 s.
System: 0.0 s, 0.0 s.
run your program under the control of pdb, the Python debugger.
This allows you to execute your program step by step, watch variables,
etc. Internally, what IPython does is similar to calling::'execfile("YOURFILENAME")')
with a breakpoint set on line 1 of your file. You can change the line
number for this automatic breakpoint to be <N> by using the -bN option
(where N must be an integer). For example::
%run -d -b40 myscript
will set the first breakpoint at line 40 in Note that
the first breakpoint must be set on a line which actually does
something (not a comment or docstring) for it to stop execution.
Or you can specify a breakpoint in a different file::
%run -d -b myscript
When the pdb debugger starts, you will see a (Pdb) prompt. You must
first enter 'c' (without quotes) to start execution up to the first
Entering 'help' gives information about the use of the debugger. You
can easily see pdb's full documentation with "import pdb;"
at a prompt.
run program under the control of the Python profiler module (which
prints a detailed report of execution times, function calls, etc).
You can pass other options after -p which affect the behavior of the
profiler itself. See the docs for %prun for details.
In this mode, the program's variables do NOT propagate back to the
IPython interactive namespace (because they remain in the namespace
where the profiler executes them).
Internally this triggers a call to %prun, see its documentation for
details on the options available specifically for profiling.
There is one special usage for which the text above doesn't apply:
if the filename ends with .ipy[nb], the file is run as ipython script,
just as if the commands were written on IPython prompt.
specify module name to load instead of script path. Similar to
the -m option for the python interpreter. Use this option last if you
want to combine with other %run options. Unlike the python interpreter
only source modules are allowed no .pyc or .pyo files.
For example::
%run -m example
will run the example module.
disable shell-like glob expansion of arguments.
# Logic to handle issue #3664
# Add '--' after '-m <module_name>' to ignore additional args passed to a module.
if '-m' in parameter_s and '--' not in parameter_s:
argv = shlex.split(parameter_s, posix=( == 'posix'))
for idx, arg in enumerate(argv):
if arg and arg.startswith('-') and arg != '-':
if arg == '-m':
argv.insert(idx + 2, '--')
# Positional arg, break
parameter_s = ' '.join(shlex.quote(arg) for arg in argv)
# get arguments and set sys.argv for program to be run.
opts, arg_lst = self.parse_options(parameter_s,
mode='list', list_all=1)
if "m" in opts:
modulename = opts["m"][0]
modpath = find_mod(modulename)
if modpath is None:
warn('%r is not a valid modulename on sys.path'%modulename)
arg_lst = [modpath] + arg_lst
filename = file_finder(arg_lst[0])
except IndexError:
warn('you must provide at least a filename.')
print('\n%run:\n', oinspect.getdoc(
except IOError as e:
msg = str(e)
except UnicodeError:
msg = e.message
if filename.lower().endswith(('.ipy', '.ipynb')):
with preserve_keys(, '__file__'):['__file__'] = filename
# Control the response to exit() calls made by the script being run
exit_ignore = 'e' in opts
# Make sure that the running script gets a proper sys.argv as if it
# were run from a system shell.
save_argv = sys.argv # save it for later restoring
if 'G' in opts:
args = arg_lst[1:]
# tilde and glob expansion
args = shellglob(map(os.path.expanduser, arg_lst[1:]))
sys.argv = [filename] + args # put in the proper filename
if 'n' in opts:
name = os.path.splitext(os.path.basename(filename))[0]
name = '__main__'
if 'i' in opts:
# Run in user's interactive namespace
prog_ns =
__name__save =['__name__']
prog_ns['__name__'] = name
main_mod =
# Since '%run foo' emulates 'python' at the cmd line, we must
# set the __file__ global in the script's namespace
# TK: Is this necessary in interactive mode?
prog_ns['__file__'] = filename
# Run in a fresh, empty namespace
# The shell MUST hold a reference to prog_ns so after %run
# exits, the python deletion mechanism doesn't zero it out
# (leaving dangling references). See interactiveshell for details
main_mod =, name)
prog_ns = main_mod.__dict__
# pickle fix. See interactiveshell for an explanation. But we need to
# make sure that, if we overwrite __main__, we replace it at the end
main_mod_name = prog_ns['__name__']
if main_mod_name == '__main__':
restore_main = sys.modules['__main__']
restore_main = False
# This needs to be undone at the end to prevent holding references to
# every single object ever created.
sys.modules[main_mod_name] = main_mod
if 'p' in opts or 'd' in opts:
if 'm' in opts:
code = 'run_module(modulename, prog_ns)'
code_ns = {
'prog_ns': prog_ns,
'modulename': modulename,
if 'd' in opts:
# allow exceptions to raise in debug mode
code = 'execfile(filename, prog_ns, raise_exceptions=True)'
code = 'execfile(filename, prog_ns)'
code_ns = {
'prog_ns': prog_ns,
'filename': get_py_filename(filename),
stats = None
if 'p' in opts:
stats = self._run_with_profiler(code, opts, code_ns)
if 'd' in opts:
bp_file, bp_line = parse_breakpoint(
opts.get('b', ['1'])[0], filename)
code, code_ns, filename, bp_line, bp_file)
if 'm' in opts:
def run():, prog_ns)
if runner is None:
runner = self.default_runner
if runner is None:
runner =
def run():
runner(filename, prog_ns, prog_ns,
if 't' in opts:
# timed execution
nruns = int(opts['N'][0])
if nruns < 1:
error('Number of runs must be >=1')
except (KeyError):
nruns = 1
self._run_with_timing(run, nruns)
# regular execution
if 'i' in opts:['__name__'] = __name__save
# update IPython interactive namespace
# Some forms of read errors on the file may mean the
# __name__ key was never set; using pop we don't have to
# worry about a possible KeyError.
prog_ns.pop('__name__', None)
with preserve_keys(, '__file__'):
# It's a bit of a mystery why, but __builtins__ can change from
# being a module to becoming a dict missing some key data after
# %run. As best I can see, this is NOT something IPython is doing
# at all, and similar problems have been reported before:
# Since this seems to be done by the interpreter itself, the best
# we can do is to at least restore __builtins__ for the user on
# exit.['__builtins__'] = builtin_mod
# Ensure key global structures are restored
sys.argv = save_argv
if restore_main:
sys.modules['__main__'] = restore_main
# Remove from sys.modules the reference to main_mod we'd
# added. Otherwise it will trap references to objects
# contained therein.
del sys.modules[main_mod_name]
return stats
def _run_with_debugger(self, code, code_ns, filename=None,
bp_line=None, bp_file=None):
Run `code` in debugger with a break point.
code : str
Code to execute.
code_ns : dict
A namespace in which `code` is executed.
filename : str
`code` is ran as if it is in `filename`.
bp_line : int, optional
Line number of the break point.
bp_file : str, optional
Path to the file in which break point is specified.
`filename` is used if not given.
If the break point given by `bp_line` is not valid.
deb =
if not deb: =
deb =
# deb.checkline() fails if deb.curframe exists but is None; it can
# handle it not existing.
if hasattr(deb, 'curframe'):
del deb.curframe
# reset Breakpoint state, which is moronically kept
# in a class = 1
bdb.Breakpoint.bplist = {}
bdb.Breakpoint.bpbynumber = [None]
if bp_line is not None:
# Set an initial breakpoint to stop execution
maxtries = 10
bp_file = bp_file or filename
checkline = deb.checkline(bp_file, bp_line)
if not checkline:
for bp in range(bp_line + 1, bp_line + maxtries + 1):
if deb.checkline(bp_file, bp):
msg = ("\nI failed to find a valid line to set "
"a breakpoint\n"
"after trying up to line: %s.\n"
"Please set a valid breakpoint manually "
"with the -b option." % bp)
raise UsageError(msg)
# if we find a good linenumber, set the breakpoint
deb.do_break('%s:%s' % (bp_file, bp_line))
if filename:
# Mimic Pdb._runscript(...)
deb._wait_for_mainpyfile = True
deb.mainpyfile = deb.canonic(filename)
# Start file run
print("NOTE: Enter 'c' at the %s prompt to continue execution." % deb.prompt)
if filename:
# save filename so it can be used by methods on the deb object
deb._exec_filename = filename
while True:
try:, code_ns)
except Restart:
if filename:
deb._wait_for_mainpyfile = True
deb.mainpyfile = deb.canonic(filename)
etype, value, tb = sys.exc_info()
# Skip three frames in the traceback: the %run one,
# one inside, and the command-line typed by the
# user (run by exec in pdb itself)., value, tb, tb_offset=3)
def _run_with_timing(run, nruns):
Run function `run` and print timing information.
run : callable
Any callable object which takes no argument.
nruns : int
Number of times to execute `run`.
twall0 = time.time()
if nruns == 1:
t0 = clock2()
t1 = clock2()
t_usr = t1[0] - t0[0]
t_sys = t1[1] - t0[1]
print("\nIPython CPU timings (estimated):")
print(" User : %10.2f s." % t_usr)
print(" System : %10.2f s." % t_sys)
runs = range(nruns)
t0 = clock2()
for nr in runs:
t1 = clock2()
t_usr = t1[0] - t0[0]
t_sys = t1[1] - t0[1]
print("\nIPython CPU timings (estimated):")
print("Total runs performed:", nruns)
print(" Times : %10s %10s" % ('Total', 'Per run'))
print(" User : %10.2f s, %10.2f s." % (t_usr, t_usr / nruns))
print(" System : %10.2f s, %10.2f s." % (t_sys, t_sys / nruns))
twall1 = time.time()
print("Wall time: %10.2f s." % (twall1 - twall0))
def timeit(self, line='', cell=None, local_ns=None):
"""Time execution of a Python statement or expression
Usage, in line mode:
%timeit [-n<N> -r<R> [-t|-c] -q -p<P> -o] statement
or in cell mode:
%%timeit [-n<N> -r<R> [-t|-c] -q -p<P> -o] setup_code
Time execution of a Python statement or expression using the timeit
module. This function can be used both as a line and cell magic:
- In line mode you can time a single-line statement (though multiple
ones can be chained with using semicolons).
- In cell mode, the statement in the first line is used as setup code
(executed but not timed) and the body of the cell is timed. The cell
body has access to any variables created in the setup code.
-n<N>: execute the given statement <N> times in a loop. If this value
is not given, a fitting value is chosen.
-r<R>: repeat the loop iteration <R> times and take the best result.
Default: 3
-t: use time.time to measure the time, which is the default on Unix.
This function measures wall time.
-c: use time.clock to measure the time, which is the default on
Windows and measures wall time. On Unix, resource.getrusage is used
instead and returns the CPU user time.
-p<P>: use a precision of <P> digits to display the timing result.
Default: 3
-q: Quiet, do not print result.
-o: return a TimeitResult that can be stored in a variable to inspect
the result in more details.
In [1]: %timeit pass
8.26 ns ± 0.12 ns per loop (mean ± std. dev. of 7 runs, 100000000 loops each)
In [2]: u = None
In [3]: %timeit u is None
29.9 ns ± 0.643 ns per loop (mean ± std. dev. of 7 runs, 10000000 loops each)
In [4]: %timeit -r 4 u == None
In [5]: import time
In [6]: %timeit -n1 time.sleep(2)
The times reported by %timeit will be slightly higher than those
reported by the script when variables are accessed. This is
due to the fact that %timeit executes the statement in the namespace
of the shell, compared with, which uses a single setup
statement to import function or create variables. Generally, the bias
does not matter as long as results from are not mixed with
those from %timeit."""
opts, stmt = self.parse_options(line,'n:r:tcp:qo',
posix=False, strict=False)
if stmt == "" and cell is None:
timefunc = timeit.default_timer
number = int(getattr(opts, "n", 0))
default_repeat = 7 if timeit.default_repeat < 7 else timeit.default_repeat
repeat = int(getattr(opts, "r", default_repeat))
precision = int(getattr(opts, "p", 3))
quiet = 'q' in opts
return_result = 'o' in opts
if hasattr(opts, "t"):
timefunc = time.time
if hasattr(opts, "c"):
timefunc = clock
timer = Timer(timer=timefunc)
# this code has tight coupling to the inner workings of timeit.Timer,
# but is there a better way to achieve that the code stmt has access
# to the shell namespace?
transform =
if cell is None:
# called as line magic
ast_setup ="pass")
ast_stmt =
ast_setup =
ast_stmt =
ast_setup =
ast_stmt =
# Check that these compile to valid Python code *outside* the timer func
# Invalid code may become valid when put inside the function & loop,
# which messes up error messages.
#, "<magic-timeit-setup>", "exec"), "<magic-timeit-stmt>", "exec")
# This codestring is taken from timeit.template - we fill it in as an
# AST, so that we can apply our AST transformations to the user code
# without affecting the timing code.
timeit_ast_template = ast.parse('def inner(_it, _timer):\n'
' setup\n'
' _t0 = _timer()\n'
' for _i in _it:\n'
' stmt\n'
' _t1 = _timer()\n'
' return _t1 - _t0\n')
timeit_ast = TimeitTemplateFiller(ast_setup, ast_stmt).visit(timeit_ast_template)
timeit_ast = ast.fix_missing_locations(timeit_ast)
# Track compilation time so it can be reported if too long
# Minimum time above which compilation time will be reported
tc_min = 0.1
t0 = clock()
code =, "<magic-timeit>", "exec")
tc = clock()-t0
ns = {}
glob =
# handles global vars with same name as local vars. We store them in conflict_globs.
if local_ns is not None:
conflict_globs = {}
for var_name, var_val in glob.items():
if var_name in local_ns:
conflict_globs[var_name] = var_val
exec(code, glob, ns)
timer.inner = ns["inner"]
# This is used to check if there is a huge difference between the
# best and worst timings.
# Issue:
if number == 0:
# determine number so that 0.2 <= total time < 2.0
for index in range(0, 10):
number = 10 ** index
time_number = timer.timeit(number)
if time_number >= 0.2:
all_runs = timer.repeat(repeat, number)
best = min(all_runs) / number
worst = max(all_runs) / number
timeit_result = TimeitResult(number, repeat, best, worst, all_runs, tc, precision)
# Restore global vars from conflict_globs
if local_ns is not None:
if len(conflict_globs) > 0:
if not quiet :
# Check best timing is greater than zero to avoid a
# ZeroDivisionError.
# In cases where the slowest timing is lesser than a micosecond
# we assume that it does not really matter if the fastest
# timing is 4 times faster than the slowest timing or not.
if worst > 4 * best and best > 0 and worst > 1e-6:
print("The slowest run took %0.2f times longer than the "
"fastest. This could mean that an intermediate result "
"is being cached." % (worst / best))
print( timeit_result )
if tc > tc_min:
print("Compiler time: %.2f s" % tc)
if return_result:
return timeit_result
def time(self,line='', cell=None, local_ns=None):
"""Time execution of a Python statement or expression.
The CPU and wall clock times are printed, and the value of the
expression (if any) is returned. Note that under Win32, system time
is always reported as 0, since it can not be measured.
This function can be used both as a line and cell magic:
- In line mode you can time a single-line statement (though multiple
ones can be chained with using semicolons).
- In cell mode, you can time the cell body (a directly
following statement raises an error).
This function provides very basic timing functionality. Use the timeit
magic for more control over the measurement.
In [1]: %time 2**128
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00
Out[1]: 340282366920938463463374607431768211456L
In [2]: n = 1000000
In [3]: %time sum(range(n))
CPU times: user 1.20 s, sys: 0.05 s, total: 1.25 s
Wall time: 1.37
Out[3]: 499999500000L
In [4]: %time print 'hello world'
hello world
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00
Note that the time needed by Python to compile the given expression
will be reported if it is more than 0.1s. In this example, the
actual exponentiation is done by Python at compilation time, so while
the expression can take a noticeable amount of time to compute, that
time is purely due to the compilation:
In [5]: %time 3**9999;
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s
In [6]: %time 3**999999;
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s
Compiler : 0.78 s
# fail immediately if the given expression can't be compiled
if line and cell:
raise UsageError("Can't use statement directly after '%%time'!")
if cell:
expr =
expr =
# Minimum time above which parse time will be reported
tp_min = 0.1
t0 = clock()
expr_ast =
tp = clock()-t0
# Apply AST transformations
expr_ast =
# Minimum time above which compilation time will be reported
tc_min = 0.1
if len(expr_ast.body)==1 and isinstance(expr_ast.body[0], ast.Expr):
mode = 'eval'
source = '<timed eval>'
expr_ast = ast.Expression(expr_ast.body[0].value)
mode = 'exec'
source = '<timed exec>'
t0 = clock()
code =, source, mode)
tc = clock()-t0
# skew measurement as little as possible
glob =
wtime = time.time
# time execution
wall_st = wtime()
if mode=='eval':
st = clock2()
out = eval(code, glob, local_ns)
end = clock2()
st = clock2()
exec(code, glob, local_ns)
end = clock2()
out = None
wall_end = wtime()
# Compute actual times and report
wall_time = wall_end-wall_st
cpu_user = end[0]-st[0]
cpu_sys = end[1]-st[1]
cpu_tot = cpu_user+cpu_sys
# On windows cpu_sys is always zero, so no new information to the next print
if sys.platform != 'win32':
print("CPU times: user %s, sys: %s, total: %s" % \
print("Wall time: %s" % _format_time(wall_time))
if tc > tc_min:
print("Compiler : %s" % _format_time(tc))
if tp > tp_min:
print("Parser : %s" % _format_time(tp))
return out
def macro(self, parameter_s=''):
"""Define a macro for future re-execution. It accepts ranges of history,
filenames or string objects.
%macro [options] name n1-n2 n3-n4 ... n5 .. n6 ...
-r: use 'raw' input. By default, the 'processed' history is used,
so that magics are loaded in their transformed version to valid
Python. If this option is given, the raw input as typed at the
command line is used instead.
-q: quiet macro definition. By default, a tag line is printed
to indicate the macro has been created, and then the contents of
the macro are printed. If this option is given, then no printout
is produced once the macro is created.
This will define a global variable called `name` which is a string
made of joining the slices and lines you specify (n1,n2,... numbers
above) from your input history into a single string. This variable
acts like an automatic function which re-executes those lines as if
you had typed them. You just type 'name' at the prompt and the code
The syntax for indicating input ranges is described in %history.
Note: as a 'hidden' feature, you can also use traditional python slice
notation, where N:M means numbers N through M-1.
For example, if your history contains (print using %hist -n )::
44: x=1
45: y=3
46: z=x+y
47: print x
48: a=5
49: print 'x',x,'y',y
you can create a macro with lines 44 through 47 (included) and line 49
called my_macro with::
In [55]: %macro my_macro 44-47 49
Now, typing `my_macro` (without quotes) will re-execute all this code
in one pass.
You don't need to give the line-numbers in order, and any given line
number can appear multiple times. You can assemble macros with any
lines from your input history in any order.
The macro is a simple object which holds its value in an attribute,
but IPython's display system checks for macros and executes them as
code instead of printing them when you type their name.
You can view a macro's contents by explicitly printing it with::
print macro_name
opts,args = self.parse_options(parameter_s,'rq',mode='list')
if not args: # List existing macros
return sorted(k for k,v in if isinstance(v, Macro))
if len(args) == 1:
raise UsageError(
"%macro insufficient args; usage '%macro name n1-n2 n3-4...")
name, codefrom = args[0], " ".join(args[1:])
#print 'rng',ranges # dbg
lines =, 'r' in opts)
except (ValueError, TypeError) as e:
macro = Macro(lines), macro)
if not ( 'q' in opts) :
print('Macro `%s` created. To execute, type its name (without quotes).' % name)
print('=== Macro contents: ===')
print(macro, end=' ')
@magic_arguments.argument('output', type=str, default='', nargs='?',
help="""The name of the variable in which to store output.
This is a object with stdout/err attributes
for the text of the captured output.
CapturedOutput also has a show() method for displaying the output,
and __call__ as well, so you can use that to quickly display the
If unspecified, captured output is discarded.
@magic_arguments.argument('--no-stderr', action="store_true",
help="""Don't capture stderr."""
@magic_arguments.argument('--no-stdout', action="store_true",
help="""Don't capture stdout."""
@magic_arguments.argument('--no-display', action="store_true",
help="""Don't capture IPython's rich display."""
def capture(self, line, cell):
"""run the cell, capturing stdout, stderr, and IPython's rich display() calls."""
args = magic_arguments.parse_argstring(self.capture, line)
out = not args.no_stdout
err = not args.no_stderr
disp = not args.no_display
with capture_output(out, err, disp) as io:
if args.output:[args.output] = io
def parse_breakpoint(text, current_file):
'''Returns (file, line) for file:line and (current_file, line) for line'''
colon = text.find(':')
if colon == -1:
return current_file, int(text)
return text[:colon], int(text[colon+1:])
def _format_time(timespan, precision=3):
"""Formats the timespan in a human readable form"""
if timespan >= 60.0:
# we have more than a minute, format that in a human readable form
# Idea from
parts = [("d", 60*60*24),("h", 60*60),("min", 60), ("s", 1)]
time = []
leftover = timespan
for suffix, length in parts:
value = int(leftover / length)
if value > 0:
leftover = leftover % length
time.append(u'%s%s' % (str(value), suffix))
if leftover < 1:
return " ".join(time)
# Unfortunately the unicode 'micro' symbol can cause problems in
# certain terminals.
# See bug:
# Try to prevent crashes by being more secure than it needs to
# E.g. eclipse is able to print a µ, but has no sys.stdout.encoding set.
units = [u"s", u"ms",u'us',"ns"] # the save value
if hasattr(sys.stdout, 'encoding') and sys.stdout.encoding:
units = [u"s", u"ms",u'\xb5s',"ns"]
scaling = [1, 1e3, 1e6, 1e9]
if timespan > 0.0:
order = min(-int(math.floor(math.log10(timespan)) // 3), 3)
order = 3
return u"%.*g %s" % (precision, timespan * scaling[order], units[order])