Important

This documentation covers IPython versions 6.0 and higher. Beginning with version 6.0, IPython stopped supporting compatibility with Python versions lower than 3.3 including all versions of Python 2.7.

If you are looking for an IPython version compatible with Python 2.7, please use the IPython 5.x LTS release and refer to its documentation (LTS is the long term support release).

Module: core.magics.execution

Implementation of execution-related magic functions.

4 Classes

class IPython.core.magics.execution.TimeitResult(loops, repeat, best, worst, all_runs, compile_time, precision)

Bases: 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)

__init__(loops, repeat, best, worst, all_runs, compile_time, precision)
class IPython.core.magics.execution.TimeitTemplateFiller(ast_setup, ast_stmt)

Bases: NodeTransformer

Fill in the AST template for timing execution.

This is quite closely tied to the template definition, which is in ExecutionMagics.timeit().

__init__(ast_setup, ast_stmt)
visit_For(node)

Fill in the statement to be timed

visit_FunctionDef(node)

Fill in the setup statement

class IPython.core.magics.execution.Timer(stmt='pass', setup='pass', timer=<built-in function perf_counter>, globals=None)

Bases: Timer

Timer class that explicitly uses self.inner

which is an undocumented implementation detail of CPython, not shared by PyPy.

timeit(number=1000000)

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.

class IPython.core.magics.execution.ExecutionMagics(**kwargs: Any)

Bases: Magics

Magics related to code execution, debugging, profiling, etc.

__init__(shell)

Create a configurable given a config config.

Parameters:
  • config (Config) – If this is empty, default values are used. If config is a Config instance, it will be used to configure the instance.

  • parent (Configurable instance, optional) – The parent Configurable instance of this object.

Notes

Subclasses of Configurable must call the __init__() method of Configurable before doing anything else and using super():

class MyConfigurable(Configurable):
    def __init__(self, config=None):
        super(MyConfigurable, self).__init__(config=config)
        # Then any other code you need to finish initialization.

This ensures that instances will be configured properly.

capture(line, cell)
%capture [--no-stderr] [--no-stdout] [--no-display] [output]

run the cell, capturing stdout, stderr, and IPython’s rich display() calls.

positional arguments:
output The name of the variable in which to store output. This is a

utils.io.CapturedIO 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 output. If unspecified, captured output is discarded.

options:
--no-stderr

Don’t capture stderr.

--no-stdout

Don’t capture stdout.

--no-display

Don’t capture IPython’s rich display.

code_wrap(line, cell=None)
%code_wrap [--remove] [--list] [--list-all] [name]

Simple magic to quickly define a code transformer for all IPython’s future input.

__code__ and __ret__ are special variable that represent the code to run and the value of the last expression of __code__ respectively.

Examples

In [1]: %%code_wrap before_after
   ...: print('before')
   ...: __code__
   ...: print('after')
   ...: __ret__
   ...: 

In [2]: 1
before
after
Out[2]: 1

In [3]: %code_wrap --list
before
before_after
after

In [4]: %code_wrap --list-all
before
before_after :
    print('before')
    __code__
    print('after')
    __ret__

after

In [5]: %code_wrap --remove before_after
before
after
positional arguments:

name

options:
--remove

remove the current transformer

--list

list existing transformers name

--list-all

list existing transformers name and code template

debug(line='', cell=None, local_ns=None)
%debug [--breakpoint FILE:LINE] [statement ...]

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.

Changed in version 7.3: When running code, user variables are no longer expanded, the magic line is always left unmodified.

positional arguments:
statement Code to run in debugger. You can omit this in cell

magic mode.

options:
--breakpoint <FILE:LINE>, -b <FILE:LINE>

Set break point at LINE in FILE.

macro(parameter_s='')

Define a macro for future re-execution. It accepts ranges of history, filenames or string objects.

Usage:

%macro [options] name n1-n2 n3-n4 … n5 .. n6 …

Options:

-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 executes.

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)
pdb(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.

prun(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] code… code…

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 function.

The given statement (which doesn’t require quote marks) is run via the python profiler in a manner similar to the profile.run() function. Namespaces are internally managed to work correctly; profile.run cannot be used in IPython because it makes certain assumptions about namespaces which do not hold under IPython.

Options:

-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.

-r

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 defined:

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.

-q

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] filename.py [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; profile.help()

Changed in version 7.3: User variables are no longer expanded, the magic line is always left unmodified.

run(parameter_s='', runner=None, file_finder=<function get_py_filename>)

Run the named file inside IPython as a program.

Usage:

%run [-n -i -e -G]
     [( -t [-N<N>] | -d [-b<N>] | -p [profile options] )]
     ( -m mod | filename ) [args]

The filename argument should be either a pure Python script (with extension .py), or a file with custom IPython syntax (such as magics). If the latter, the file can be either a script with .ipy extension, or a Jupyter notebook with .ipynb extension. When running a Jupyter notebook, the output from print statements and other displayed objects will appear in the terminal (even matplotlib figures will open, if a terminal-compliant backend is being used). Note that, at the system command line, the jupyter run command offers similar functionality for executing notebooks (albeit currently with some differences in supported options).

Parameters after the filename are passed as command-line arguments to the program (put in sys.argv). Then, control returns to IPython’s prompt.

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.

On Windows systems, the use of single quotes ' when specifying a file is not supported. Use double quotes ".

Options:

-n

__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.

-i

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.

-e

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.

-t

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 uniq_stable.py):

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.
-d

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:

pdb.run('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 myscript.py. 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 myotherfile.py:20 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 breakpoint.

Entering ‘help’ gives information about the use of the debugger. You can easily see pdb’s full documentation with “import pdb;pdb.help()” at a prompt.

-p

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.

-m

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.

-G

disable shell-like glob expansion of arguments.

tb(s)

Print the last traceback.

Optionally, specify an exception reporting mode, tuning the verbosity of the traceback. By default the currently-active exception mode is used. See %xmode for changing exception reporting modes.

Valid modes: Plain, Context, Verbose, and Minimal.

time(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.

Changed in version 7.3: User variables are no longer expanded, the magic line is always left unmodified.

Examples

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

The time needed by Python to compile the given expression will be reported if it is more than 0.1s.

In the example below, 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
timeit(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 code 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.

Options: -n<N>: execute the given statement <N> times in a loop. If <N> is not provided, <N> is determined so as to get sufficient accuracy.

-r<R>: number of repeats <R>, each consisting of <N> loops, and take the average result. Default: 7

-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.

Changed in version 7.3: User variables are no longer expanded, the magic line is always left unmodified.

Examples

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 timeit.py script when variables are accessed. This is due to the fact that %timeit executes the statement in the namespace of the shell, compared with timeit.py, which uses a single setup statement to import function or create variables. Generally, the bias does not matter as long as results from timeit.py are not mixed with those from %timeit.

1 Function

IPython.core.magics.execution.parse_breakpoint(text, current_file)

Returns (file, line) for file:line and (current_file, line) for line