Function for timing executions (inspired by MATLAB tic toc)

Question

Inspired by MATLAB's tic/toc I've written a short helper function for calculating execution time.

from time import time

def tic():
    """Simple helper function for timing executions.

    Returns a closure that holds current time when calling tic().

    Usage:
    toc = tic()
    //some code
    print(toc())
    """
    t = time()
    return (lambda: (time() - t))

I'm well aware that there are python modules (e.g. timeit) that handle this kind of problem. However I do not want to time the execution of a whole script. I'm using this function in an interavtive shell for querying a mssql server.

What do you think? Is this good practice?

Answer 1

I have a minor stylistic point, but you don't need (and shouldn't use) brackets around return values. Neither the lambda itself nor the lambda's return value.

return lambda: time() - t

It is minor but it actually confused me and made me think there was more of an expression there because of how rarely brackets are used like this.

Answer 2

timeit can time arbitrary expressions, so I don't see a good use case for what you're doing here. In fact, it could be considered bad practice in the sense that timing information, which is normally in the same category as debugging code, shouldn't be built into your program or function or whatever. You should be able to add that on "outside", only if needed. That's what timeit allows you to do.

Of course, sometimes it is actually useful to include timing information as part of your program. Even in that case, it seems like overkill to use a lambda function. A simpler way would be

def main_timed():
    start = time()
    main()
    print time() - start

But I don't see any major disadvantage to the way you're doing it. It's just that other programmers will probably find it kind of odd.