What is timeit in python

Question

I always read the code to calculate the time like this way    timeit function     Can you explain what means     here    I think  the     is always used to replace something in a string  like  s means replace a string   d replace a data   but I have no idea about this case

User · Answer

Line magics are prefixed with the   character and work much like OS command-line calls  they get as an argument the rest of the line  where arguments are passed without parentheses or quotes  Cell magics are prefixed with a double     and they are functions that get as an argument not only the rest of the line  but also the lines below it in a separate argument

User · Answer

I just wanted to add a very subtle point about   timeit  Given it runs the  quot magics quot  on the cell  you ll get error    UsageError  Line magic function   timeit not found    if there is any code comment lines above   timeit  In other words  ensure that   timeit is the first command in your cell  I know it s a small point all the experts will say duh to  but just wanted to add my half a cent for the young wizards starting out with magic tricks

User · Answer

This is known as a line magic in iPython   They are unique in that their arguments only extend to the end of the current line  and magics themselves are really structured for command line development   timeit is used to time the execution of code    If you wanted to see all of the magics you can use  you could simply type    lsmagic   to get a list of both line magics and cell magics    Some further magic information from documentation here      IPython has a system of commands we call magics that provide effectively a mini command language that is orthogonal to the syntax of Python and is extensible by the user with new commands  Magics are meant to be typed interactively  so they use command-line conventions  such as using whitespace for separating arguments  dashes for options and other conventions typical of a command-line environment    Depending on whether you are in line or cell mode  there are two different ways to use  timeit  Your question illustrates the first way   In  1    timeit range 100    vs   In  1     timeit          x   range 100

User · Answer

I would just like to add another useful advantage of using  timeit to answer by mu   that     You can also make use of current console variables without passing the whole code snippet as in case of timeit timeit to built the variable that is built in an another enviroment that timeit works    PS  I know this should be a comment to answer above but I currently don t have enough reputation for that  hope what I write will be helpful to someone and help me earn enough reputation to comment next time

User · Answer

IPython intercepts those  they re called built-in magic commands  here s the list  https   ipython org ipython-doc dev interactive magics html  You can also create your own custom magics  https   ipython org ipython-doc dev config custommagics html  Your timeit is here https   ipython org ipython-doc dev interactive magics html magic-timeit

User · Answer

timeit is an ipython magic function  which can be used to time a particular piece of code  A single execution statement  or a single method    From the docs       timeit  Time execution of a Python statement or expression  Usage  in line mode       timeit  -n lt N gt  -r lt R gt   -t -c  -q -p lt P gt  -o  statement    To use it  for example if we want to find out whether using xrange is any faster than using range  you can simply do   In  1    timeit for   in range 1000   True 10000 loops  best of 3  37 8   s per loop  In  2    timeit for   in xrange 1000   True 10000 loops  best of 3  29 6   s per loop   And you will get the timings for them   The major advantage of  timeit are    that you don t have to import timeit timeit from the standard library  and run the code multiple times to figure out which is the better approach   timeit will automatically calculate number of runs required for your code based on a total of 2 seconds execution window  You can also make use of current console variables without passing the whole code snippet as in case of timeit timeit to built the variable that is built in an another environment that timeit works

[python] What is %timeit in python?

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