Python Stopwatch

This module contains a Stopwatch class with a context manager and a decorator function to time your code easily

Below are some examples:

First import the Stopwatch class

from stopwatch import Stopwatch

For the tutorial we're going to use this function which takes a bit more than a second to run

def func():
    x = ''
    for i in range(1_000_000):
        x += str(i)

Instantiate the Stopwatch class:

sw = Stopwatch()

sw.start()
func()
sw.stop()

print('Time elapsed:', sw.time_elapsed)

Time elapsed: 1.2138440999988234

Or we can simply print the instance which will return a nicely formatted string:

print(sw)

Time elapsed: 1.214

Using the 'with' statement:

with Stopwatch() as sw:
    func()
    print(sw)

Time elapsed: 1.138

You can also pass an instance of a class to automatically add the time taken to the total elapsed time of the instance:

sw = Stopwatch()

with sw:
    func()

func()

with sw:
    func()

print(sw)

Time elapsed: 2.328

The above example is the equivalent of:

sw = Stopwatch()

sw.start()
func()
sw.stop()

func()

sw.start()
func()
sw.stop()

print(sw)

Time elapsed: 2.324

You can also use the decorator to time a function every time you run it

First import the decorator:

from stopwatch import time_it

Add it to your function:

@time_it()
def func():
    x = ''
    for i in range(1_000_000):
        x += str(i)

Now the function will return a tuple with the time taken and the output of the function (which in our case is None)

print(func())

(1.1769665000028908, None)

You can also add the time taken to an existing Stopwatch instance like so:

sw = Stopwatch()

@time_it(stopwatch=sw)
def func():
    x = ''
    for i in range(1_000_000):
        x += str(i)

Call the function twice:

print('Out:', func())
print(sw)
print('Out:', func())
print(sw)

Out: (1.2755557999989833, None)
Time elapsed: 1.276
Out: (1.3011283000014373, None)
Time elapsed: 2.577