A High Order Timer Function

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A high order function is a function that takes a function as an argument or returns a function.
One use case is when you want to do something more with your function without altering the passed-on function.

For example, if we want to time the execution of a function the not optimal way.

import time
def cubeit(x):
    time.sleep(1)
    return x * x * x
t_start = time.perf_counter()
res = cubeit(144)
t_end = time.perf_counter()
t_run = t_end - t_start
print(f'It took cubeit {t_run:.2f} sec to complete')
print(res)

It took cubeit 1.00 sec to complete
2985984

It’s not optimal! What if you want to perform the same task on another function.

The High order function approach, passing the function cubeit to our timer function.

import time
def timer_func(f):
    def wrapper_timer(*args):
        t_start = time.perf_counter()
        res = f(*args)
        t_end = time.perf_counter()
        t_run = t_end - t_start
        print(f'It took {f.__name__} {t_run:.2f} sec to complete')
        return res
    return wrapper_timer
def cubeit(x):
    time.sleep(1)
    return x * x * x
foo = timer_func(cubeit)
res = foo(144)
print(res)

It took cubeit 1.00 sec to complete
2985984

Well, this is cluttered! is there a neat way to achieve the same result?

Yes, the pythonic way of using decorators.

import time
def timer_func(f):
    def wrapper_timer(*args):
        t_start = time.perf_counter()
        res = f(*args)
        t_end = time.perf_counter()
        t_run = t_end - t_start
        print(f'It took {f.__name__} {t_run:.2f} sec to complete')
        return res
    return wrapper_timer
@timer_func
def cubeit(x):
    time.sleep(1)
    return x * x * x
res = cubeit(144)
print(res)
It took cubeit 1.00 sec to complete
2985984

Note that @timer_fun is equivalent to timer_fun(cubeit).
So, what else can I do with decorators, logging to an external file!