Python performance tests - basic

In

Brute force (datetime)

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import datetime

start_time = datetime.datetime.now()
# insert code snippet here
end_time = datetime.datetime.now()
print(end_time - start_time)

Abstraction (timeit)

Run the snippet a million times and return an average execution time as a result

  • Example snippet

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    [(a, b) for a in (1, 3, 5) for b in (2, 4, 6)]

  • Test snippet

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    import timeit
    # default: 1 million times
    timeit.timeit("[(a, b) for a in (1, 3, 5) for b in (2, 4, 6)]")
    # define the number of times
    timeit.timeit("[(a, b) for a in (1, 3, 5) for b in (2, 4, 6)]", number=1000)

  • Further ideas

    • Get a list of execution times
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      import timeit
      timeit.repeat("[(a, b) for a in (1, 3, 5) for b in (2, 4, 6)]")
      # get the best result
      min(timeit.repeat("[(a, b) for a in (1, 3, 5) for b in (2, 4, 6)]"))

Statistics (cProfile)

  • Example snippet

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    [(a, b) for a in (1, 3, 5) for b in (2, 4, 6)]

  • Test snippet

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    import cProfile
    cProfile.run("[(a, b) for a in (1, 3, 5) for b in (2, 4, 6)]")

  • Results data (Row = function that was executed)

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    4 function calls in 0.000 seconds 

      Ordered by: standard name 

      ncalls tottime percall cumtime percall filename:lineno(function) 
        1 0.000 0.000 0.000 0.000 <string>:1(<listcomp>) 
        1 0.000 0.000 0.000 0.000 <string>:1(<module>) 
        1 0.000 0.000 0.000 0.000 {built-in method builtins.exec} 
        1 0.000 0.000 0.000 0.000 {method 'disable' of '\_lsprof.Profiler' objects}
    • ncalls: the number of times that particular function was called
      • This number may actually be written as a fraction (e.g. 3/1) where the first value is the number of total calls and the second value is the number of primitive calls (not recursive).
    • tottime: total amount of time the function spent executing not including calls to subfunctions.
    • percall (first): the ratio of tottime to ncalls (i.e. the average amount of time spent in this function excluding subfunctions).
    • cumtime : the total amount of time the function spent executing including calls to subfunctions.
    • percall (second): the ratio of cumtime to primitive calls (i.e. the average amount of time spent in this function).
    • filename:lineno(function): filename, line number, and function.

External Libraries