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 · 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 --> 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 --> 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

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

Use timeit  http   docs python org library timeit html

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

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

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

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

Examples related to python

Examples related to datetime