How do I get time of a Python program s execution

Question

I have a command line program in Python that takes a while to finish  I want to know the exact time it takes to finish running   I ve looked at the timeit module  but it seems it s only for small snippets of code  I want to time the whole program

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The simplest way in Python   import time start time   time time   main   print  ---  s seconds ---     time time   - start time     This assumes that your program takes at least a tenth of second to run   Prints   --- 0 764891862869 seconds ---

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The time of a Python program s execution measure could be inconsistent depending on    Same program can be evaluated using different algorithms Running time varies between algorithms Running time varies between implementations Running time varies between computers Running time is not predictable based on small inputs   This is because the most effective way is using the  Order of Growth  and learn the Big  O  notation to do it properly   Anyway  you can try to evaluate the performance of any Python program in specific machine counting steps per second using this simple algorithm  adapt this to the program you want to evaluate  import time  now   time time   future   now   10 step   4   Why 4 steps  Because until here already four operations executed while time time    lt  future      step    3   Why 3 again  Because a while loop executes one comparison and one plus equal statement step    4   Why 3 more  Because one comparison starting while when time is over plus the final assignment of step   1 and print statement print str int step   10       steps per second

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For the data folks using Jupyter Notebook  In a cell  you can use Jupyter s   time magic command to measure the execution time     time   x  2 for x in range 10000     Output  CPU times  user 4 54 ms  sys  0 ns  total  4 54 ms Wall time  4 12 ms   This will only capture the execution time of a particular cell  If you d like to capture the execution time of the whole notebook  i e  program   you can create a new notebook in the same directory and in the new notebook execute all cells   Suppose the notebook above is called example notebook ipynb  In a new notebook within the same directory     Convert your notebook to a  py script   jupyter nbconvert --to script example notebook ipynb    Run the example notebook with -t flag for time  run -t example notebook   Output  IPython CPU timings  estimated     User           0 00 s    System         0 00 s  Wall time        0 00 s

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I used a very simple function to time a part of code execution   import time def timing        start time   time time       return lambda x  print      2f s      format time time   - start time  x     And to use it  just call it before the code to measure to retrieve function timing  and then call the function after the code with comments  The time will appear in front of the comments  For example   t   timing   train   pd read csv  train csv                           dtype                                id   str                               vendor id   str                               pickup datetime   str                               dropoff datetime   str                               passenger count   int                               pickup longitude   np float64                               pickup latitude   np float64                               dropoff longitude   np float64                               dropoff latitude   np float64                               store and fwd flag   str                               trip duration   int                                                     parse dates     pickup datetime    dropoff datetime                         t  Loaded    rows data from  train   format len train      Then the output will look like this    9 35s  Loaded 1458644 rows data from  train

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Use line profiler   line profiler will profile the time individual lines of code take to execute  The profiler is implemented in C via Cython in order to reduce the overhead of profiling   from line profiler import LineProfiler import random  def do stuff numbers       s   sum numbers      l    numbers i  43 for i in range len numbers        m     hello  str numbers i   for i in range len numbers     numbers    random randint 1 100  for i in range 1000   lp   LineProfiler   lp wrapper   lp do stuff  lp wrapper numbers  lp print stats     The results will be   Timer unit  1e-06 s  Total time  0 000649 s File   lt ipython-input-2-2e060b054fea gt  Function  do stuff at line 4  Line        Hits         Time  Per Hit     Time  Line Contents                                                                     4                                           def do stuff numbers        5         1           10     10 0      1 5      s   sum numbers       6         1          186    186 0     28 7      l    numbers i  43 for i in range len numbers         7         1          453    453 0     69 8      m     hello  str numbers i   for i in range len numbers

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I liked Paul McGuire s answer too and came up with a context manager form which suited my needs more   import datetime as dt import timeit  class TimingManager object          Context Manager used with the statement  with  to time some execution       Example       with TimingManager   as t           Code to time              clock   timeit default timer      def   enter   self                                   self start   self clock           self log   n  gt  Start Timing                return self      def   exit   self  exc type  exc val  exc tb                                   self endlog            return False      def log self  s  elapsed None              Log current time and elapsed time if present           param s  Text to display  use      to format the text with             the current time           param elapsed  Elapsed time to display  Dafault  None  no display                      print s format self  secondsToStr self clock              if elapsed is not None               print  Elapsed time     n  format elapsed       def endlog self              Log time for the end of execution with elapsed time                      self log    gt  End Timing       self now         def now self              Return current elapsed time as hh mm ss string           return  String                      return str dt timedelta seconds   self clock   - self start        def  secondsToStr self  sec              Convert timestamp to h mm ss string           param sec  Timestamp                      return str dt datetime fromtimestamp sec

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I like the output the datetime module provides  where time delta objects show days  hours  minutes  etc  as necessary in a human-readable way   For example   from datetime import datetime start time   datetime now     do your work here end time   datetime now   print  Duration      format end time - start time     Sample output e g   Duration  0 00 08 309267   or  Duration  1 day  1 51 24 269711   As J F  Sebastian mentioned  this approach might encounter some tricky cases with local time  so it s safer to use   import time from datetime import timedelta start time   time monotonic   end time   time monotonic   print timedelta seconds end time - start time

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Even better for Linux  time    time -v python rhtest2 py      Command being timed   python rhtest2 py      User time  seconds   4 13     System time  seconds   0 07     Percent of CPU this job got  91      Elapsed  wall clock  time  h mm ss or m ss   0 04 58     Average shared text size  kbytes   0     Average unshared data size  kbytes   0     Average stack size  kbytes   0     Average total size  kbytes   0     Maximum resident set size  kbytes   0     Average resident set size  kbytes   0     Major  requiring I O  page faults  15     Minor  reclaiming a frame  page faults  5095     Voluntary context switches  27     Involuntary context switches  279     Swaps  0     File system inputs  0     File system outputs  0     Socket messages sent  0     Socket messages received  0     Signals delivered  0     Page size  bytes   4096     Exit status  0

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This is the simplest way to get the elapsed time for the program   Write the following code at the end of your program   import time print time clock

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Later answer  but I use the built-in timeit  import timeit code to test    quot  quot  quot  a   range 100000  b      for i in a      b append i 2   quot  quot  quot  elapsed time   timeit timeit code to test  number 500  print elapsed time    10 159821493085474    Wrap all your code  including any imports you may have  inside code to test  number argument specifies the amount of times the code should repeat  Demo

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To use metakermit s updated answer for Python nbsp 2 7  you will require the monotonic package   The code would then be as follows   from datetime import timedelta from monotonic import monotonic  start time   monotonic   end time   monotonic   print timedelta seconds end time - start time

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I tried and found time difference using the following scripts   import time  start time   time perf counter    main code here  print  time perf counter   - start time   seconds

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Similar to the response from  rogeriopvl I added a slight modification to convert to hour minute seconds using the same library for long running jobs   import time start time   time time   main   seconds   time time   - start time print  Time Taken    time strftime   H  M  S  time gmtime seconds      Sample Output  Time Taken  00 00 08

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I put this timing py module into my own site-packages directory  and just insert import timing at the top of my module   import atexit from time import clock  def secondsToStr t       return   d  02d  02d  03d              reduce lambda ll b   divmod ll 0  b    ll 1                  t 1000   1000 60 60    line       40 def log s  elapsed None       print line     print secondsToStr clock      -   s     if elapsed          print  Elapsed time    elapsed     print line     print  def endlog        end   clock       elapsed   end-start     log  End Program   secondsToStr elapsed    def now        return secondsToStr clock     start   clock   atexit register endlog  log  Start Program     I can also call timing log from within my program if there are significant stages within the program I want to show   But just including import timing will print the start and end times  and overall elapsed time    Forgive my obscure secondsToStr function  it just formats a floating point number of seconds to hh mm ss sss form    Note  A Python 3 version of the above code can be found here or here

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For functions  I suggest using this simple decorator I created  def timeit method       def timed  args    kw           ts   time time           result   method  args    kw          te   time time           if  log time  in kw              name   kw get  log name   method   name   upper                kw  log time   name    int  te - ts    1000          else              print   r   2 22f ms     method   name     te - ts    1000           return result     return timed   timeit def foo        do some work        foo   0 000953 ms

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In Linux or Unix     time python yourprogram py   In Windows  see this StackOverflow question  How do I measure execution time of a command on the Windows command line   For more verbose output      time -v python yourprogram py     Command being timed   python3 yourprogram py      User time  seconds   0 08     System time  seconds   0 02     Percent of CPU this job got  98      Elapsed  wall clock  time  h mm ss or m ss   0 00 10     Average shared text size  kbytes   0     Average unshared data size  kbytes   0     Average stack size  kbytes   0     Average total size  kbytes   0     Maximum resident set size  kbytes   9480     Average resident set size  kbytes   0     Major  requiring I O  page faults  0     Minor  reclaiming a frame  page faults  1114     Voluntary context switches  0     Involuntary context switches  22     Swaps  0     File system inputs  0     File system outputs  0     Socket messages sent  0     Socket messages received  0     Signals delivered  0     Page size  bytes   4096     Exit status  0

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First  install humanfriendly package by opening Command Prompt  CMD  as administrator and type there - pip install humanfriendly  Code   from humanfriendly import format timespan import time begin time   time time     Put your code here end time   time time   - begin time print  Total execution time     format timespan end time     Output

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Just use the timeit module  It works with both Python 2 and Python 3   import timeit  start   timeit default timer      All the program statements stop   timeit default timer   execution time   stop - start  print  Program Executed in   str execution time     It returns time in seconds   It returns in seconds and you can have your execution time  It is simple  but you should write these in thew main function which starts program execution  If you want to get the execution time even when you get an error then take your parameter  Start  to it and calculate there like   def sample function start   kwargs        try             Your statements      except             except statements run when your statements raise an exception          stop   timeit default timer            execution time   stop - start          print  Program executed in     str execution time

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I was having the same problem in many places  so I created a convenience package horology  You can install it with pip install horology and then do it in the elegant way   from horology import Timing  with Timing name  Important calculations          prepare       do your stuff       finish sth     will output   Important calculations  12 43 ms   Or even simpler  if you have one function    from horology import timed   timed def main              will output   main  7 12 h   It takes care of units and rounding  It works with python 3 6 or newer

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Timeit is a class in Python used to calculate the execution time of small blocks of code   Default timer is a method in this class which is used to measure the wall clock timing  not CPU execution time  Thus other process execution might interfere with this  Thus it is useful for small blocks of code   A sample of the code is as follows   from timeit import default timer as timer  start  timer      Some logic  end   timer    print  Time taken    end-start

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This is Paul McGuire s answer that works for me  Just in case someone was having trouble running that one   import atexit from time import clock  def reduce function  iterable  initializer None       it   iter iterable      if initializer is None          value   next it      else          value   initializer     for element in it          value   function value  element      return value  def secondsToStr t       return   d  02d  02d  03d              reduce lambda ll b   divmod ll 0  b    ll 1                  t 1000   1000 60 60    line       40 def log s  elapsed None       print  line      print  secondsToStr clock      -   s      if elapsed          print   Elapsed time    elapsed      print  line   def endlog        end   clock       elapsed   end-start     log  End Program   secondsToStr elapsed    def now        return secondsToStr clock     def main        start   clock       atexit register endlog      log  Start Program     Call timing main   from your program after importing the file

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You can use the Python profiler cProfile to measure CPU time and additionally how much time is spent inside each function and how many times each function is called  This is very useful if you want to improve performance of your script without knowing where to start  This answer to another Stack nbsp Overflow question is pretty good  It s always good to have a look in the documentation too   Here s an example how to profile a script using cProfile from a command line     python -m cProfile euler048 py  1007 function calls in 0 061 CPU seconds  Ordered by  standard name ncalls  tottime  percall  cumtime  percall filename lineno function      1    0 000    0 000    0 061    0 061  lt string gt  1  lt module gt    1000    0 051    0 000    0 051    0 000 euler048 py 2  lt lambda gt       1    0 005    0 005    0 061    0 061 euler048 py 2  lt module gt       1    0 000    0 000    0 061    0 061  execfile      1    0 002    0 002    0 053    0 053  map      1    0 000    0 000    0 000    0 000  method  disable  of   lsprof Profiler objects      1    0 000    0 000    0 000    0 000  range      1    0 003    0 003    0 003    0 003  sum

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You do this simply in Python  There is no need to make it complicated  import time  start   time localtime   end   time localtime    quot  quot  quot Total execution time in minutes   quot  quot  quot  print end tm min - start tm min   quot  quot  quot Total execution time in seconds   quot  quot  quot  print end tm sec - start tm sec

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There is a timeit module which can be used to time the execution times of Python code   It has detailed documentation and examples in Python documentation  26 6  timeit     Measure execution time of small code snippets

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from time import time start time   time       end time   time   time taken   end time - start time   time taken is in seconds hours  rest   divmod time taken 3600  minutes  seconds   divmod rest  60

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I ve looked at the timeit module  but it seems it s only for small snippets of code  I want to time the whole program      python -mtimeit -n1 -r1 -t -s  from your module import main   main      It runs your module main   function one time and print the elapsed time using time time   function as a timer   To emulate  usr bin time in Python see Python subprocess with  usr bin time  how to capture timing info but ignore all other output    To measure CPU time  e g   don t include time during time sleep    for each function  you could use profile module  cProfile on Python 2      python3 -mprofile your module py   You could pass -p to timeit command above if you want to use the same timer as profile module uses   See How can you profile a Python script

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The following snippet prints elapsed time in a nice human readable  lt HH MM SS gt  format   import time from datetime import timedelta  start time   time time        Perform lots of computations     elapsed time secs   time time   - start time  msg    Execution took   s secs  Wall clock time     timedelta seconds round elapsed time secs    print msg

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import time  start time   time clock   main   print time clock   - start time   seconds    time clock   returns the processor time  which allows us to calculate only the time used by this process  on Unix anyway   The documentation says  in any case  this is the function to use for benchmarking Python or timing algorithms

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I really like Paul McGuire s answer  but I use Python 3  So for those who are interested  here s a modification of his answer that works with Python 3 on  nix  I imagine  under Windows  that clock   should be used instead of time       python3 import atexit from time import time  strftime  localtime from datetime import timedelta  def secondsToStr elapsed None       if elapsed is None          return strftime   Y- m- d  H  M  S   localtime        else          return str timedelta seconds elapsed    def log s  elapsed None       line       40     print line      print secondsToStr     -   s      if elapsed          print  Elapsed time    elapsed      print line      print    def endlog        end   time       elapsed   end-start     log  End Program   secondsToStr elapsed    start   time   atexit register endlog  log  Start Program     If you find this useful  you should still up-vote his answer instead of this one  as he did most of the work

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Following this answer created a simple but convenient instrument  import time from datetime import timedelta  def start time measure message None       if message          print message      return time monotonic    def end time measure start time  print prefix None       end time   time monotonic       if print prefix          print print prefix   str timedelta seconds end time - start time        return end time  Usage  total start time   start time measure       start time   start time measure  Doing something        Do something end time measure start time   Done in     start time   start time measure  Doing something else        Do something else end time measure start time   Done in     end time measure total start time   Total time      The output  Doing something    Done in  0 00 01 218000 Doing something else    Done in  0 00 01 313000 Total time  0 00 02 672000

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time clock       Deprecated since version 3 3  The behavior of this function depends   on the platform  use perf counter   or process time   instead    depending on your requirements  to have a well-defined behavior    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    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    start   time process time       do something elapsed    time process time   - start

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If you want to measure time in microseconds  then you can use the following version  based completely on the answers of Paul McGuire and Nicojo - it s Python nbsp 3 code  I ve also added some colour to it   import atexit from time import time from datetime import timedelta  datetime   def seconds to str elapsed None       if elapsed is None          return datetime now   strftime   Y- m- d  H  M  S  f       else          return str timedelta seconds elapsed     def log txt  elapsed None       colour cyan     033 36m      colour reset     033 0 0 39m      colour red     033 31m      print   n     colour cyan       TIMING  gt       seconds to str        ---- gt      txt     n    colour reset      if elapsed          print   n     colour red      TIMING  gt  Elapsed time    gt      elapsed     n    colour reset    def end log        end   time       elapsed   end-start     log  End Program   seconds to str elapsed     start   time   atexit register end log  log  Start Program     log      function that prints out the timing information   txt     first argument to log  and its string to mark timing   atexit     Python module to register functions that you can call when the program exits

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In IPython   timeit  any script    def foo         run bar py timeit foo

[python] How do I get time of a Python program's execution?

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