具有可变格式的装饰器计时器功能（小数位）？

Question

I am trying to create a decorator for a timer so that i can easily call @decoratortimer for my functions to time the amount of time taken my function took to run.

However, I cant seem to be able to make my decorator function variable such that I can change the number of decimal places as per user request.

import time

def decoratortimer(decimal):
    def decoratorfunction(f):
        def wrap(*args, **kwargs):
            time1 = time.time()
            result = f(*args, **kwargs)
            time2 = time.time()
            print('{:s} function took {:{}f} ms'.format(f.__name__, ((time2-time1)*1000.0), decimal ))
            return result
        return wrap
    return decoratorfunction

@decoratortimer(2)
def callablefunction(name):
    print(name)
print(callablefunction('John'))

#outputs "callablefunction function took 1.008511 ms"

As you can see from my code, I've formatted my string as such,

print('{:s} function took {:{}f} ms'.format(f.__name__, ((time2-time1)*1000.0), decimal ))

My expected output is that it is supposed to print out callablefunction function took 1.01 ms because i've passed in the integer value of 2 for my decimal places in @decoratortimer .

Could I be formatting my string wrongly? I have looked at this and tried to emulate it but still cant get my decorator function to work! Please help, I cant seem to wrap my head around this. (No pun intended).

Answer 1

Replace {:{}f} with {:.{}f} to get the number of decimal places.

Another topic: consider using time.monotonic instead of time.time for this case. If the system clock gets an update during your function runs, the result may become negative. time.monotonic is guaranteed to increase. The values themselves are not relevant, only the difference between them is. ( docs )