`IPython.core.magics.execution:ExecutionMagics.timeit`

source: /IPython/core/magics/execution.py :1046

Signature

def timeit ( self , line = '' , cell = None , local_ns = None )

Summary

Time execution of a Python statement or expression

Extended Summary

Usage, in line mode

%timeit [-n<N> -r<R> [-t|-c] -q -p<P> [-o|-v <V>]] statement

or in cell mode

%%timeit [-n<N> -r<R> [-t|-c] -q -p<P> [-o|-v <V>]] 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.
-v <V>: Like -o, but save the TimeitResult directly to variable <V>.

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``.

Aliases

IPython.core.magics.ExecutionMagics.timeit