How do you determine a processing time in Python

Question

I m new to Python  and confused by the date time documentation   I want to compute the time that it takes to perform a computation   In java  I would write   long timeBefore   System currentTimeMillis    doStuff    long timeAfter   System currentTimeMillis    elapsed time   timeAfter - timeBefore    I m sure it s even easier in Python  Can anyone help

User · Accepted Answer

Equivalent in python would be    gt  gt  gt  import time  gt  gt  gt  tic   time clock    gt  gt  gt  toc   time clock    gt  gt  gt  toc - tic   If you are trying to find the best performing method then you should probably have a look at timeit

User · Answer

python -m timeit -h

User · Answer

If all you want is the time between two points in code  and it seems that s what you want  I have written tic   toc   functions ala Matlab s implementation  The basic use case is   tic        some code that runs for an interesting amount of time      toc      OUTPUT    Elapsed time is  32 42123 seconds   Super  incredibly easy to use  a sort of fire-and-forget kind of code  It s available on Github s Gist https   gist github com tyleha 5174230

User · Answer

Building on and updating a number of earlier responses  thanks  SilentGhost  nosklo  Ramkumar  a simple portable timer would use timeit s default timer       gt  gt  gt  import timeit  gt  gt  gt  tic timeit default timer    gt  gt  gt    Do Stuff  gt  gt  gt  toc timeit default timer    gt  gt  gt  toc - tic  elapsed time in seconds   This will return the elapsed wall clock  real  time  not CPU time  And as described in the timeit documentation chooses the most precise available real-world timer depending on the platform    ALso  beginning with Python 3 3 this same functionality is available with the time perf counter performance counter  Under 3 3  timeit default timer   refers to this new counter   For more precise complex performance calculations  timeit includes more sophisticated calls for automatically timing small code snippets including averaging run time over a defined set of repetitions

User · Answer

For some further information on how to determine the processing time  and a comparison of a few methods  some mentioned already in the answers of this post  - specifically  the difference between    start   time time     versus the now obsolete  as of 3 3  time clock   is deprecated   start   time clock     see this other article on Stackoverflow here    Python - time clock   vs  time time   - accuracy   If nothing else  this will work good    start   time time        do something  elapsed    time time   - start

User · Answer

You can implement two tic   and tac   functions  where tic   captures the time which it is called  and tac   prints the time difference since tic   was called  Here is a short implementation   import time   start time   time time    def tic        global  start time       start time   time time    def tac        t sec   round time time   -  start time       t min  t sec    divmod t sec 60       t hour t min    divmod t min 60       print  Time passed    hour   min   sec  format t hour t min t sec     Now in your code you can use it as    tic   do some stuff   tac     and it will  for example  output   Time passed  0hour 7min 26sec   See also    Python s datetime library  https   docs python org 2 library datetime html Python s time library  https   docs python org 2 library time html

User · Answer

For Python 3 3 and later time process time   is very nice   import time  t   time process time    do some stuff elapsed time   time process time   - t

User · Answer

I also got a requirement to calculate the process time of some code lines  So I tried the approved answer and I got this warning  DeprecationWarning  time clock has been deprecated in Python 3 3 and will be removed from Python 3 8  use time perf counter or time process time instead  So python will remove time clock   from Python 3 8  You can see more about it from issue  13270  This warning suggest two function instead of time clock    In the documentation also mention about this warning in-detail in time clock   section   Deprecated since version 3 3  will be removed in version 3 8  The behaviour of this function depends on the platform  use perf counter   or process time   instead  depending on your requirements  to have a well defined behaviour   Let s look at in-detail both functions    time perf counter     Return the value  in fractional seconds  of a performance counter  i e  a clock with the highest available resolution to measure a short duration  It does include time elapsed during sleep and is system-wide  The reference point of the returned value is undefined  so that only the difference between the results of consecutive calls is valid  New in version 3 3   So if you want it as nanoseconds  you can use time perf counter ns   and if your code consist with time sleep secs   it will also count  Ex - import time   def func x       time sleep 5      return x   x   lst    1  2  3  tic   time perf counter   print  func x  for x in lst   toc   time perf counter   print toc - tic      1  4  9    15 0041916 -- gt  output including 5 seconds sleep time    time process time     Return the value  in fractional seconds  of the sum of the system and user CPU time of the current process  It does not include time elapsed during sleep  It is process-wide by definition  The reference point of the returned value is undefined  so that only the difference between the results of consecutive calls is valid  New in version 3 3   So if you want it as nanoseconds  you can use time process time ns   and if your code consist with time sleep secs   it won t count  Ex - import time   def func x       time sleep 5      return x   x   lst    1  2  3  tic   time process time   print  func x  for x in lst   toc   time process time   print toc - tic      1  4  9    0 0 -- gt  output excluding 5 seconds sleep time   Please note both time perf counter ns   and time process time ns   come up with Python 3 7 onward

User · Answer

Use timeit  http   docs python org library timeit html

[python] How do you determine a processing time in Python?

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