我如何使用timeit来比较我自己的函数(如“insertion_sort”和“tim_sort”)的性能?


当前回答

我发现使用timeit最简单的方法是从命令行:

鉴于test.py:

def InsertionSort(): ...
def TimSort(): ...

像这样运行timeit:

% python -mtimeit -s'import test' 'test.InsertionSort()'
% python -mtimeit -s'import test' 'test.TimSort()'

其他回答

# Генерация целых чисел

def gen_prime(x):
    multiples = []
    results = []
    for i in range(2, x+1):
        if i not in multiples:
            results.append(i)
            for j in range(i*i, x+1, i):
                multiples.append(j)

    return results


import timeit

# Засекаем время

start_time = timeit.default_timer()
gen_prime(3000)
print(timeit.default_timer() - start_time)

# start_time = timeit.default_timer()
# gen_prime(1001)
# print(timeit.default_timer() - start_time)

我发现使用timeit最简单的方法是从命令行:

鉴于test.py:

def InsertionSort(): ...
def TimSort(): ...

像这样运行timeit:

% python -mtimeit -s'import test' 'test.InsertionSort()'
% python -mtimeit -s'import test' 'test.TimSort()'

如果你想在交互式Python会话中使用timeit,有两个方便的选项:

Use the IPython shell. It features the convenient %timeit special function: In [1]: def f(x): ...: return x*x ...: In [2]: %timeit for x in range(100): f(x) 100000 loops, best of 3: 20.3 us per loop In a standard Python interpreter, you can access functions and other names you defined earlier during the interactive session by importing them from __main__ in the setup statement: >>> def f(x): ... return x * x ... >>> import timeit >>> timeit.repeat("for x in range(100): f(x)", "from __main__ import f", number=100000) [2.0640320777893066, 2.0876040458679199, 2.0520210266113281]

如果你想快速比较两个代码/函数块,你可以这样做:

import timeit

start_time = timeit.default_timer()
func1()
print(timeit.default_timer() - start_time)

start_time = timeit.default_timer()
func2()
print(timeit.default_timer() - start_time)

您将创建两个函数,然后运行与此类似的程序。 注意,您希望选择相同的执行/运行数来比较apple和apple。 这是在Python 3.7下测试的。

下面是便于复制的代码

!/usr/local/bin/python3
import timeit

def fibonacci(n):
    """
    Returns the n-th Fibonacci number.
    """
    if(n == 0):
        result = 0
    elif(n == 1):
        result = 1
    else:
        result = fibonacci(n-1) + fibonacci(n-2)
    return result

if __name__ == '__main__':
    import timeit
    t1 = timeit.Timer("fibonacci(13)", "from __main__ import fibonacci")
    print("fibonacci ran:",t1.timeit(number=1000), "milliseconds")