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 ---
answered Oct 13, 2009 at 0:00
rogeriopvlrogeriopvl
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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
answered Oct 12, 2009 at 23:59
stevehasteveha
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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.
answered Oct 13, 2009 at 2:08
PaulMcGPaulMcG
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7
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))
answered Sep 29, 2014 at 11:55
metakermitmetakermit
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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»
Shidouuu
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answered Oct 13, 2009 at 1:25
newacctnewacct
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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 ;).
Georgy
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answered Sep 10, 2012 at 2:03
NicojoNicojo
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7
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 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 <string>:1(<module>)
1000 0.051 0.000 0.051 0.000 euler048.py:2(<lambda>)
1 0.005 0.005 0.061 0.061 euler048.py:2(<module>)
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}
answered Jan 2, 2014 at 0:35
jacwahjacwah
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2
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))
djamaile
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answered Sep 18, 2017 at 19:08
Ravi KumarRavi Kumar
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1
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)
answered May 18, 2016 at 3:49
YasYas
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1
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
import time
start_time = time.perf_counter ()
for x in range(1, 100):
print(x)
end_time = time.perf_counter ()
print(end_time - start_time, "seconds")
Suraj Rao
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answered Jun 20, 2021 at 9:11
1
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.
answered Jul 28, 2018 at 16:48
MattMatt
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The following snippet prints elapsed time in a nice human readable <HH:MM:SS>
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)
answered Jul 1, 2016 at 22:24
SandeepSandeep
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1
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
answered Mar 12, 2020 at 5:27
user 923227user 923227
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1
For functions, I suggest using this simple decorator I created.
def timeit(method):
def timed(*args, **kwargs):
ts = time.time()
result = method(*args, **kwargs)
te = time.time()
if 'log_time' in kwargs:
name = kwargs.get('log_name', method.__name__.upper())
kwargs['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()
# 'foo' 0.000953 ms
answered Oct 29, 2020 at 10:24
Nikita TonkoskurNikita Tonkoskur
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3
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)
The6thSense
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answered Apr 6, 2016 at 7:45
Qina YanQina Yan
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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?
answered Mar 3, 2015 at 9:04
jfsjfs
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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.
answered Dec 7, 2019 at 22:05
hanshans
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4
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=> 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('=> 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))
answered Jan 29, 2015 at 15:42
GallGall
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In IPython, «timeit» any script:
def foo():
%run bar.py
timeit foo()
answered May 20, 2015 at 14:40
B.KocisB.Kocis
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1
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: <ipython-input-2-2e060b054fea>
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))]
answered Mar 28, 2018 at 5:43
Yu JiaaoYu Jiaao
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1
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'
answered Aug 7, 2018 at 5:42
Tao WangTao Wang
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0
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")
answered May 8, 2020 at 4:44
Hafez AhmadHafez Ahmad
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1
You do this simply in Python. There is no need to make it complicated.
import time
start = time.localtime()
end = time.localtime()
"""Total execution time in minutes$ """
print(end.tm_min - start.tm_min)
"""Total execution time in seconds$ """
print(end.tm_sec - start.tm_sec)
swateek
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answered Feb 16, 2019 at 5:18
1
Later answer, but I use the built-in timeit
:
import timeit
code_to_test = """
a = range(100000)
b = []
for i in a:
b.append(i*2)
"""
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
answered Feb 25, 2020 at 0:15
Pedro LobitoPedro Lobito
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3
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)
answered Nov 16, 2017 at 2:16
0
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:
Georgy
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answered Apr 16, 2020 at 10:40
Amar KumarAmar Kumar
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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
answered Nov 26, 2020 at 13:05
Nick LegendNick Legend
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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.
answered Apr 8, 2015 at 0:24
Saurabh RanaSaurabh Rana
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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() < 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")
answered Jul 31, 2017 at 15:13
ManuManu
1124 bronze badges
In this article, we will discuss how to check the execution time of a Python script.
There are many Python modules like time, timeit and datetime module in Python which can store the time at which a particular section of the program is being executed. By manipulating or getting the difference between times of beginning and ending at which a particular section is being executed, we can calculate the time it took to execute the section.
The following methods can be used to compute time difference:
- Python time module provides various time-related functions. This module comes under Python’s standard utility modules. time.time() method of the Time module is used to get the time in seconds since epoch. The handling of leap seconds is platform-dependent.
- Python datetime module defines a function that can be primarily used to get the current time and date. now() function Return the current local date and time, which is defined under the datetime module.
- Python timeit module runs your snippet of code n number of times (the default value is, 1000000) so that you get the statistically most relevant measurement of code execution time.
Using the time module check the execution time of Python
Example 1: Measuring time taken for a code segment by recording start and end times
Computing the time using the time module and time.time() function. We have computed the time of the above program, which came out of the order 10^-3. We can check for the time by increasing the number of computations using the same algorithms.
Python3
import
time
start
=
time.time()
a
=
0
for
i
in
range
(
1000
):
a
+
=
(i
*
*
100
)
end
=
time.time()
print
(
"The time of execution of above program is :"
,
(end
-
start)
*
10
*
*
3
,
"ms"
)
Output:
The time of execution of above program is : 0.77056884765625 ms
Example 2: Measuring time taken for a code segment by adding up the time required per iteration
Checking times for execution of the program for different numbers of computations. We see a general trend in the increase in time of computation for an increase in the number of execution. However, it may not show any linear trend or fixed increments.
Python3
import
time
for
j
in
range
(
100
,
5501
,
100
):
start
=
time.time()
a
=
0
for
i
in
range
(j):
a
+
=
(i
*
*
100
)
end
=
time.time()
print
(f
"Iteration: {j}tTime taken: {(end-start)*10**3:.03f}ms"
)
Output:
Iteration: 100 Time taken: 0.105ms Iteration: 200 Time taken: 0.191ms Iteration: 300 Time taken: 0.291ms Iteration: 400 Time taken: 0.398ms Iteration: 500 Time taken: 0.504ms Iteration: 600 Time taken: 0.613ms Iteration: 700 Time taken: 0.791ms ... Iteration: 5400 Time taken: 6.504ms Iteration: 5500 Time taken: 6.630ms
Explanation: Here we have truncated the output for representation purpose. But if we compare the iterations from 100 to 700 they are less than 1ms. But towards the end of the loop, each iteration taking ~7ms. Thus, there is an increase in time taken as the number of iterations have increased. This is generally because, the inner loop iterate more number of time depending on each outer iteration.
Using the DateTime module check the execution time
Using the datetime module in Python and datetime.now() function to record timestamp of start and end instance and finding the difference to get the code execution time.
Python3
from
datetime
import
datetime
start
=
datetime.now()
a
=
0
for
i
in
range
(
1000
):
a
+
=
(i
*
*
100
)
end
=
datetime.now()
td
=
(end
-
start).total_seconds()
*
10
*
*
3
print
(f
"The time of execution of above program is : {td:.03f}ms"
)
Output:
The time of execution of above program is : 0.766ms
Using timeit module check the execution time
This would give us the execution time of any program. This module provides a simple way to find the execution time of small bits of Python code. It provides the timeit() method to do the same. The module function timeit.timeit(stmt, setup, timer, number) accepts four arguments:
- stmt which is the statement you want to measure; it defaults to ‘pass’.
- setup, which is the code that you run before running the stmt; it defaults to ‘pass’. We generally use this to import the required modules for our code.
- timer, which is a timeit.Timer object; usually has a sensible default value, so you don’t have to worry about it.
- The number, which is the number of executions you’d like to run the stmt.
Example 1: Using timeit inside Python code snippet to measure execution time
Python3
import
timeit
mysetup
=
"from math import sqrt"
mycode
=
exec_time
=
timeit.timeit(stmt
=
mycode,
setup
=
mysetup,
number
=
1000000
)
*
10
*
*
3
print
(f
"The time of execution of above program is : {exec_time:.03f}ms"
)
Output:
The time of execution of above program is : 71.161ms
Example 2: Using timeit from command line to measure execution time
We can measure time taken by simple code statements without the need to write new Python files, using timeit CLI interface.
timeit supports various command line inputs, Here we will note a few of the mos common arguments:
- -s [–setup]: Setup code to run before running the code statement.
- -n [–number]: Number of times to execute the statement.
- –p [–process]: Measure the process time of the code execution, instead of the wall-clock time.
- Statement: The code statements to test the execution time, taken as a positional argument.
timeit CLI statement:
python -m timeit -s "import random" "l = [x**9 for x in range(random.randint(1000, 1500))]"
Output:
500 loops, best of 5: 503 usec per loop
After reading this article, you’ll learn: –
- How to calculate the program’s execution time in Python
- Measure the total time elapsed to execute the code block in seconds, milliseconds, minutes, and hours
- Also, get the execution time of functions and loops.
In this article, We will use the following four ways to measure the execution time in Python: –
time.time()
function: measure the the total time elapsed to execute the script in seconds.time.process_time()
: measure the CPU execution time of a code- timeit module: measure the execution time of a small piece of a code including the single line of code as well as multiple lines of code
- DateTime module: measure the execution time in the hours-minutes-seconds format.
To measure the code performance, we need to calculate the time taken by the script/program to execute. Measuring the execution time of a program or parts of it will depend on your operating system, Python version, and what you mean by ‘time’.
Before proceeding further, first, understand what time is.
Table of contents
- Wall time vs. CPU time
- How to Measure Execution Time in Python
- Example: Get Program’s Execution Time in Seconds
- Get Execution Time in Milliseconds
- Get Execution Time in Minutes
- Get Program’s CPU Execution Time using process_time()
- timeit module to measure the execution time of a code
- Example: Measure the execution time of a function
- Measure the execution time of a single line of code
- Measure the execution time of a multiple lines of code
- DateTime Module to determine the script’s execution time
- Conclusion
Wall time vs. CPU time
We often come across two terms to measure the execution time: Wall clock time and CPU time.
So it is essential to define and differentiate these two terms.
- Wall time (also known as clock time or wall-clock time) is simply the total time elapsed during the measurement. It’s the time you can measure with a stopwatch. It is the difference between the time at which a program finished its execution and the time at which the program started. It also includes waiting time for resources.
- CPU Time, on the other hand, refers to the time the CPU was busy processing the program’s instructions. The time spent waiting for other task to complete (like I/O operations) is not included in the CPU time. It does not include the waiting time for resources.
The difference between the Wall time and CPU time can occur from architecture and run-time dependency, e.g., programmed delays or waiting for system resources to become available.
For example, a program reports that it has used “CPU time 0m0.2s, Wall time 2m4s”. It means the program was active for 2 minutes and four seconds. Still, the computer’s processor spent only 0.2 seconds performing calculations for the program. May be program was waiting for some resources to become available.
At the beginning of each solution, I listed explicitly which kind of time each method measures.
So depending upon why you are measuring your program’s execution time, you can choose to calculate the Wall or CPU time.
The Python time module provides various time-related functions, such as getting the current time and suspending the calling thread’s execution for the given number of seconds. The below steps show how to use the time module to calculate the program’s execution time.
- Import time module
The time module comes with Python’s standard library. First, Import it using the import statement.
- Store the start time
Now, we need to get the start time before executing the first line of the program. To do this, we will use the
time()
function to get the current time and store it in a ‘start_time‘ variable before the first line of the program.
Thetime()
function of a time module is used to get the time in seconds since epoch. The handling of leap seconds is platform-dependent. - Store the end time
Next, we need to get the end time before executing the last line.
Again, we will use thetime()
function to get the current time and store it in the ‘end_time‘ variable before the last line of the program. - Calculate the execution time
The difference between the end time and start time is the execution time. Get the execution time by subtracting the start time from the end time.
Example: Get Program’s Execution Time in Seconds
Use this solution in the following cases: –
- Determine the execution time of a script
- Measure the time taken between lines of code.
Note: This solution measures the Wall time, i.e., total elapsed time, not a CPU time.
import time
# get the start time
st = time.time()
# main program
# find sum to first 1 million numbers
sum_x = 0
for i in range(1000000):
sum_x += i
# wait for 3 seconds
time.sleep(3)
print('Sum of first 1 million numbers is:', sum_x)
# get the end time
et = time.time()
# get the execution time
elapsed_time = et - st
print('Execution time:', elapsed_time, 'seconds')
Output:
Sum of first 1 million numbers is: 499999500000 Execution time: 3.125561475753784 seconds
Note: It will report more time if your computer is busy with other tasks. If your script was waiting for some resources, the execution time would increase because the waiting time will get added to the final result.
Get Execution Time in Milliseconds
Use the above example to get the execution time in seconds, then multiply it by 1000 to get the final result in milliseconds.
Example:
# get execution time in milliseconds
res = et - st
final_res = res * 1000
print('Execution time:', final_res, 'milliseconds')
Output:
Sum of first 1 million numbers is: 499999500000
Execution time: 3125.988006591797 milliseconds
Get Execution Time in Minutes
Use the above example to get the execution time in seconds, then divide it by 60 to get the final result in minutes.
Example:
# get execution time in minutes
res = et - st
final_res = res / 60
print('Execution time:', final_res, 'minutes')
Output:
Sum of first 1 million numbers is: 499999500000 Execution time: 0.05200800895690918 minutes
Do you want better formatting?
Use the strftime() to convert the time in a more readable format like (hh-mm-ss) hours-minutes-seconds.
import time
st = time.time()
# your code
sum_x = 0
for i in range(1000000):
sum_x += i
time.sleep(3)
print('Sum:', sum_x)
elapsed_time = time.time() - st
print('Execution time:', time.strftime("%H:%M:%S", time.gmtime(elapsed_time)))
Output:
Sum: 499999500000
Execution time: 00:00:03
Get Program’s CPU Execution Time using process_time()
The time.time()
will measure the wall clock time. If you want to measure the CPU execution time of a program use the time.process_time()
instead of time.time()
.
Use this solution if you don’t want to include the waiting time for resources in the final result. Let’s see how to get the program’s CPU execution time.
import time
# get the start time
st = time.process_time()
# main program
# find sum to first 1 million numbers
sum_x = 0
for i in range(1000000):
sum_x += i
# wait for 3 seconds
time.sleep(3)
print('Sum of first 1 million numbers is:', sum_x)
# get the end time
et = time.process_time()
# get execution time
res = et - st
print('CPU Execution time:', res, 'seconds')
Output:
Sum of first 1 million numbers is: 499999500000 CPU Execution time: 0.234375 seconds
Note:
Because we are calculating the CPU execution time of a program, as you can see, the program was active for more than 3 seconds. Still, those 3 seconds were not added in CPU time because the CPU was ideal, and the computer’s processor spent only 0.23 seconds performing calculations for the program.
timeit module to measure the execution time of a code
Python timeit module provides a simple way to time small piece of Python code. It has both a Command-Line Interface as well as a callable one. It avoids many common traps for measuring execution times.
timeit module is useful in the following cases: –
- Determine the execution time of a small piece of code such as functions and loops
- Measure the time taken between lines of code.
The timeit()
function: –
The timeit.timeit()
returns the time (in seconds) it took to execute the code number times.
timeit.timeit(stmt='pass', setup='pass', timer=<default timer>, number=1000000, globals=None)
Note: This solution measures the Wall time, i.e., total elapsed time, not a CPU time.
The below steps show how to measure the execution time of a code using the timeit module.
- First, create a Timer instance using the
timeit()
function - Next, Pass a code at the place of the
stmt
argument. stmt is the code for which we want to measure the time - Next, If you wish to execute a few statements before your actual code, pass them to the setup argument like import statements.
- To set a timer value, we will use the default timer provided by Python.
- Next, decide how many times you want to execute the code and pass it to the number argument. The default value of number is 1,000,000.
- In the end, we will execute the
timeit()
function with the above values to measure the execution time of the code
Example: Measure the execution time of a function
Here we will calculate the execution time of an ‘addition()’ function. We will run the addition()
function five-time to get the average execution time.
import timeit
# print addition of first 1 million numbers
def addition():
print('Addition:', sum(range(1000000)))
# run same code 5 times to get measurable data
n = 5
# calculate total execution time
result = timeit.timeit(stmt='addition()', globals=globals(), number=n)
# calculate the execution time
# get the average execution time
print(f"Execution time is {result / n} seconds")
Output:
Addition: 499999500000 Addition: 499999500000 Addition: 499999500000 Addition: 499999500000 Addition: 499999500000 Execution time is 0.03770382 seconds
Note:
If you run time-consuming code with the default number
value, it will take a lot of time. So assign less value to the number
argument Or decide how many samples do you want to measure to get the accurate execution time of a code.
- The
timeit()
functions disable the garbage collector, which results in accurate time capture. - Also, using the
timeit()
function, we can repeat the execution of the same code as many times as we want, which minimizes the influence of other tasks running on your operating system. Due to this, we can get the more accurate average execution time.
Measure the execution time of a single line of code
Run the %timeit
command on a command-line or jupyter notebook to get the execution time of a single line of code.
Example: Use %timeit
just before the line of code
%timeit [x for x in range(1000)]
# Output
2.08 µs ± 223 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)
Also, we can customize the command using the various options to enhance the profiling and capture a more accurate execution time.
- Define the number of runs using the
-r
option. For example,%timeit -r10 your_code
means run the code line 10 times. - Define the loops within each run using the
-r
and-n
option. - If you ommit the options be default it is 7 runs with each run having 1 million loops
Example: Customize the time profile operation to 10 runs and 20 loops within each run.
# Customizing number of runs and loops in %timeit
%timeit -r10 -n20 [x for x in range(1000)]
# output
1.4 µs ± 12.34 ns per loop (mean ± std. dev. of 10 runs, 20 loops each)
Measure the execution time of a multiple lines of code
Using the %%timeit
command, we can measure the execution time of multiple lines of code. The command options will remain the same.
Note: you need to replace the single percentage (%
) with double percentage (%%
) in the timeit command to get the execution time of multiple lines of a code
Example:
# Time profiling using %%timeit
%%timeit -r5 -n10
# find sum to first 1 million numbers
sum_x = 0
for i in range(1000000):
sum_x += i
# Output
10.5 µs ± 226 ns per loop (mean ± std. dev. of 5 runs, 10 loops each)
DateTime Module to determine the script’s execution time
Also, you can use the Datetime module to measure the program’s running time. Use the below steps.
Import DateTime module
- Next, store the start time using the
datetime.now()
function before the first line of a script - Next, save the end time before using the same function before the last line of a script
- In the end, calculate the execution time by subtracting the start time from an end time
Note: This solution measures the Wall time, i.e., total elapsed time, not a CPU time.
Example:
import datetime
import time
# get the start datetime
st = datetime.datetime.now()
# main program
# find sum to first 1 million numbers
sum_x = 0
for i in range(1000000):
sum_x += i
# wait for 3 seconds
time.sleep(3)
print('Sum of first 1 million numbers is:', sum_x)
# get the end datetime
et = datetime.datetime.now()
# get execution time
elapsed_time = et - st
print('Execution time:', elapsed_time, 'seconds')
Output:
Sum of first 1 million numbers is: 499999500000 Execution time: 0:00:03.115498 seconds
Conclusion
Python provides several functions to get the execution time of a code. Also, we learned the difference between Wall-clock time and CPU time to understand which execution time we need to measure.
Use the below functions to measure the program’s execution time in Python:
time.time()
: Measure the the total time elapsed to execute the code in seconds.timeit.timeit()
: Simple way to time a small piece of Python code%timeit
and%%timeit
: command to get the execution time of a single line of code and multiple lines of code.datetime.datetime.now()
: Get execution time in hours-minutes-seconds format
Also, use the time.process_time()
function to get the program’s CPU execution time.
Чтобы измерить время выполнения программы, используйте функции time.clock() или time.time(). Документы Python утверждают, что эта функция должна использоваться для целей тестирования.
Пример
import time t0= time.clock() print("Hello") t1 = time.clock() - t0 print("Time elapsed: ", t1 - t0) # CPU seconds elapsed (floating point)
Вывод
Это даст вывод —
Time elapsed: 0.0009403145040156798
Вы также можете использовать модуль timeit для правильного статистического анализа времени выполнения фрагмента кода. Он запускает фрагмент несколько раз, а затем сообщает, сколько времени занял самый короткий цикл. Вы можете использовать его следующим образом —
Пример
def f(x): return x * x import timeit timeit.repeat("for x in range(100): f(x)", "from __main__ import f", number=100000)
Вывод
Это даст вывод —
[2.0640320777893066, 2.0876040458679199, 2.0520210266113281]
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Допустим, вам необходимо узнать, сколько времени занимает выполнение той или иной функции. Используя модуль time, вы можете рассчитать это время.
import time startTime = time.time() # время начала замера # здесь пишем код, время которого необходимо измерить endTime = time.time() #время конца замера totalTime = endTime - startTime #вычисляем затраченное время print("Время, затраченное на выполнение данного кода = ", totalTime)
25 ответов
Самый простой способ в Python:
import time
start_time = time.time()
main()
print("--- %s seconds ---" % (time.time() - start_time))
Это предполагает, что для выполнения вашей программы требуется не менее десятой секунды.
Печать
--- 0.764891862869 seconds ---
rogeriopvl
13 окт. 2009, в 00:31
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Я помещаю этот модуль timing.py
в свой собственный каталог site-packages
и просто вставляю import timing
в начало моего модуля:
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")
Я также могу вызвать timing.log
из моей программы, если есть значительные этапы внутри программы, которую я хочу показать. Но только в том числе import timing
будет печатать время начала и окончания, а общая истекшая time. (пропустите мою непонятную secondsToStr
функцию, она просто форматирует число с плавающей точкой в секундах до hh: mm: ss.sss form.)
Примечание. Версия Python 3 приведенного выше кода может быть найдена здесь или здесь.
PaulMcG
13 окт. 2009, в 03:59
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import time
start_time = time.clock()
main()
print time.clock() - start_time, "seconds"
time.clock()
возвращает процессор time,, который позволяет рассчитать только time , используемые этим процессом (в любом случае, Unix). В документации говорится: «В любом случае, это функция, используемая для бенчмаркинга Python или алгоритмов синхронизации»
newacct
13 окт. 2009, в 01:44
Поделиться
Мне очень нравится ответ Пола МакГира, но я использую Python3. Итак, для тех, кому это интересно: вот модификация его ответа, которая работает с Python 3 на * nix (я полагаю, под Windows, что вместо time() следует использовать clock()):
#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")
Если вы сочтете это полезным, вы должны продолжить голосование за свой ответ вместо этого, так как он выполнил большую часть работы;).
Nicojo
10 сен. 2012, в 03:47
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Вы можете использовать Python Profiler cProfile для измерения времени процессора и, кроме того, сколько времени затрачивается внутри каждой функции и сколько раз вызывается каждая функция. Это очень полезно, если вы хотите улучшить производительность вашего скрипта, не зная, с чего начать. Этот ответ на другой вопрос довольно хорош. Всегда хорошо заглядывать в документы.
Вот пример того, как профилировать скрипт, используя cProfile из командной строки:
$ 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 <string>:1(<module>)
1000 0.051 0.000 0.051 0.000 euler048.py:2(<lambda>)
1 0.005 0.005 0.061 0.061 euler048.py:2(<module>)
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}
jacwah
02 янв. 2014, в 00:56
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Мне нравится вывод, предоставляемый модулем datetime
, где time дельта-объекты показывают дни, часы, минуты и т.д., если необходимо, с точки зрения человека.
Например:
from datetime import datetime
start_time = datetime.now()
# do your work here
end_time = datetime.now()
print('Duration: {}'.format(end_time - start_time))
Пример вывода, например
Duration: 0:00:08.309267
или
Duration: 1 day, 1:51:24.269711
Обновление: Как отметил Дж. Ф. Себастьян, этот подход может столкнуться с некоторыми сложными случаями с локальным time,, поэтому безопаснее использовать:
import time
from datetime import timedelta
start_time = time.monotonic()
end_time = time.monotonic()
print(timedelta(seconds=end_time - start_time))
metakermit
29 сен. 2014, в 13:05
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Еще лучше для Linux: /usr/bin/time
$ /usr/bin/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
Обычно просто time
является более простой оболочкой, которая затеняет более способную /usr/bin/time
.
u0b34a0f6ae
13 окт. 2009, в 07:28
Поделиться
Решение rogeriopvl отлично работает, но если вы хотите получить более конкретную информацию, вы можете использовать встроенный профилировщик python. Проверьте эту страницу:
http://docs.python.org/library/profile.html
профилировщик сообщает вам много полезной информации, такой как time , затраченная на каждую функцию
wezzy
13 окт. 2009, в 01:17
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Следующий фрагмент распечатывает прошедшее время в удобном для человека формате <HH:MM:SS>
.
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)
Sandeep
02 июль 2016, в 00:08
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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)
Qina Yan
06 апр. 2016, в 09:04
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<сильный > time.clock()
Устаревший с версии 3.3: поведение этой функции зависит на платформе: вместо этого используйте perf_counter() или process_time()в зависимости от ваших требований, чтобы иметь четко определенное поведение.
<сильный > time. perf_counter()
Возвращает значение (в дробных секундах) счетчика производительности, то есть часы с наивысшим доступным разрешением для измерения короткого продолжительность. включает time , прошедший во время сна, и в масштабе всей системы.
<сильный > time. process_time()
Возвращает значение (в дробных секундах) суммы системы и пользовательский CPU time текущего процесса. Он не включает time истекший во время сна.
start = time.process_time()
... do something
elapsed = (time.process_time() - start)
Yas
18 май 2016, в 04:26
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Ipython «timeit» любой script:
def foo():
%run bar.py
timeit foo()
ab-user
20 май 2015, в 15:42
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Я просмотрел модуль timeit , но, похоже, это только для небольших фрагментов кода. Я хочу time всю программу.
$ python -mtimeit -n1 -r1 -t -s "from your_module import main" "main()"
Он запускает your_module.main()
функцию one time и печатает прошедший time с помощью функции time.time()
в качестве таймера.
Чтобы эмулировать /usr/bin/time
в Python, см. подпроцесс Python с /usr/bin/time:, как записывать информацию о времени, но игнорировать все остальные выходные?.
Чтобы измерить CPU time (например, не включать time в течение time.sleep()
) для каждой функции, вы можете использовать модуль profile
(cProfile
на Python 2):
$ python3 -mprofile your_module.py
Вы можете передать команду -p
в timeit
выше, если вы хотите использовать тот же таймер, что и модуль profile
.
См. Как вы можете profile Python script?
jfs
03 март 2015, в 09:31
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Просто используйте timeit
модуль. Он работает как с Python 2, так и с Python 3
import timeit
start = timeit.default_timer()
#ALL THE PROGRAM STATEMETNS
stop = timeit.default_timer()
execution_time = stop - start
print("Program Executed in "+execution_time) #It returns time in sec
Он возвращается в секундах, и вы можете выполнить свое выполнение Time. Simple, но вы должны написать их в главной функции, которая запускает выполнение программы. Если вы хотите получить Execution time , даже когда вы получите ошибку, тогда возьмите свой параметр «Начать» и подсчитайте там, как
def sample_function(start,**kwargs):
try:
#your statements
Except:
#Except Statements
stop = timeit.default_timer()
execution_time = stop - start
print("Program Executed in "+execution_time)
Ravi Kumar
18 сен. 2017, в 20:17
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Мне также нравится ответ Пола МакГира и придумал форму менеджера контекста, которая соответствовала моим потребностям.
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=> 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('=> 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))
Gall
29 янв. 2015, в 15:51
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Существует модуль timeit
который можно использовать для определения времени выполнения кодов Python. Он содержит подробную документацию и примеры в документации по python (https://docs.python.org/2/library/timeit.html).
Alfie
20 окт. 2014, в 15:44
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Используйте line_profiler.
line_profiler будет профилировать время выполнения отдельных строк кода. Профилировщик реализован в C через Cython, чтобы уменьшить накладные расходы на профилирование.
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()
Результаты будут:
Timer unit: 1e-06 s
Total time: 0.000649 s
File: <ipython-input-2-2e060b054fea>
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))]
Yu Jiaao
28 март 2018, в 07:15
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Для данных людей, использующих ноутбуки Jupyter
В ячейке вы можете использовать магическую команду Jupyter %%time
для измерения времени выполнения:
%%time
[ x**2 for x in range(10000)]
Выход
Время процессора: пользовательский 4,54 мс, sys: 0 нс, всего: 4,54 мс
Время стены: 4,12 мс
Это будет захватывать только время выполнения конкретной ячейки. Если вы хотите зафиксировать время выполнения всей записной книжки (т.е. программы), вы можете создать новую записную книжку в том же каталоге и в новой записной книжке выполнить все ячейки:
Предположим, что записная книжка выше называется example_notebook.ipynb
. В новой записной книжке в том же каталоге:
# 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
Выход
Время загрузки процессора IPython (по оценкам): Пользователь: 0,00 с.
Система: 0,00 с.
Время стены: 0,00 с.
Matt
28 июль 2018, в 17:00
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Timeit — это класс в python, используемый для вычисления выполнения time небольших блоков кода.
Default_timer — это метод в этом классе, который используется для измерения времени настенных часов, а не выполнения ЦП time.. Таким образом, другое выполнение процесса может помешать этому. Таким образом, это полезно для небольших блоков кода.
Образец кода выглядит следующим образом:
from timeit import default_timer as timer
start= timer()
#some logic
end = timer()
print("Time taken:", end-start)
Utkarsh Dhawan
16 нояб. 2017, в 03:09
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Это ответ Paul McGuire, который работает для меня. На всякий случай у кого-то возникли проблемы с запуском этого.
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")
вызывать timing.main()
из вашей программы после импорта файла.
Saurabh Rana
08 апр. 2015, в 00:47
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Чтобы использовать обновленный ответ metakermit для python 2.7, вам потребуется monotonic.
Тогда код будет выглядеть следующим образом:
from datetime import timedelta
from monotonic import monotonic
start_time = monotonic()
end_time = monotonic()
print(timedelta(seconds=end_time - start_time))
H0R5E
16 июнь 2017, в 13:59
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Если вы хотите измерять время в микросекундах, то вы можете использовать следующую версию, полностью основанную на ответах Пола Макгуайра и Никохо, — это код Python3. Я также добавил немного цвета к нему:
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 = '33[36m'
colour_reset = '33[0;0;39m'
colour_red = '33[31m'
print('n ' + colour_cyan + ' [TIMING]> [' + seconds_to_str() + '] ----> ' + txt + 'n' + colour_reset)
if elapsed:
print("n " + colour_red + " [TIMING]> Elapsed time ==> " + 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() => функция, которая печатает информацию о времени.
txt ==> первый аргумент в логе и строка для отметки времени.
atexit ==> модуль python для регистрации функций, которые вы можете вызывать при выходе из программы.
Rui Carvalho
20 дек. 2018, в 02:13
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Я использовал очень простую функцию для определения времени выполнения кода:
import time
def timing():
start_time = time.time()
return lambda x: print("[{:.2f}s] {}".format(time.time() - start_time, x))
И чтобы использовать его, просто вызовите его перед кодом для измерения, чтобы получить функцию синхронизации, затем вызовите функцию после кода с комментариями, и перед комментариями появится время, например:
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)))
Тогда вывод будет выглядеть так:
[9.35s] Loaded 1458644 rows data from 'train'
Я чувствую себя немного элегантно в этом смысле.
Tao Wang
07 авг. 2018, в 06:23
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time меры выполнения программы Python может быть непоследовательной в зависимости от:
- Та же программа может быть оценена с использованием разных алгоритмов
- Запуск time изменяется между алгоритмами
- Запуск time зависит от реализации
- Запуск time варьируется между компьютерами
- Запуск time не предсказуем на основе небольших входов
Это связано с тем, что наиболее эффективным способом является использование «Ордена роста» и изучение записи «Большой буквы», чтобы сделать это правильно, https://en.wikipedia.org/wiki/Big_O_notation
В любом случае вы можете попытаться оценить производительность любой программы Python на определенных этапах машинного счета в секунду, используя этот простой алгоритм:
адаптируйте это к программе, которую хотите оценить
import time
now = time.time()
future = now + 10
step = 4 # why 4 steps? because until here already 4 operations executed
while time.time() < future:
step += 3 # why 3 again? because while loop execute 1 comparison and 1 plus equal statement
step += 4 # why 3 more? because 1 comparison starting while when time is over plus final assignment of step + 1 and print statement
print(str(int(step / 10)) + " steps per second")
Надеюсь, что это поможет вам.
Manu
31 июль 2017, в 16:51
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