Python timeit设置中的局部变量

Question

在我读到的关于timeit的所有地方,我发现只能以这种方式使用变量:

s1 = 'abc'
s2 = 'abc'
timeit.timeit('s1==s2', 'from __main__ import s1, s2', number=10**4)

要么

s1 = 'abc'
s2 = 'abc'
def func():
    timeit.time('s1==s2', 'from __main__ import s1,s2', number=10**4)

which means that you can also use timeit.timeit in a function as long as the variables are in the main program. I would like to use timeit.timeit with variables that are within the scope it is in, for example:

def func():
    s1 = 'abc'
    s2 = 'abc'
    timeit.timeit(...)

As you can see my question is:

How can I use timeit.timeit with the variables that are in the same scope, when they're both not in the main program?

Answer 1

我想将timeit.timeit与其所在范围内的变量一起使用.

TLDR:

使用lambda闭包(所谓的因为它关闭了函数中的变量):

def func():
    s1 = 'abc'
    s2 = 'abc'
    return timeit.timeit(lambda: s1 == s2)

而且我认为这只是你所要求的.

>>> func()
0.12512516975402832

说明

那么在全局范围内,您想要使用全局变量,局部范围,本地变量？在全局范围内,locals()返回相同的结果globals(),因此您可以', '.join(locals())坚持到最后'from __main__ import ',或者globals()它们在全局范围内是等效的:

>>> s1 = 'abc'
>>> s2 = 'abc'
>>> timeit.timeit('s1==s2', 'from __main__ import ' + ', '.join(globals()))
0.14271061390928885

您可以使用函数执行此操作globals(),但也不能使用locals():

s1 = 'abc'
s2 = 'abc'
def func():
    return timeit.timeit('s1==s2', 'from __main__ import ' + ', '.join(globals()))

和

>>> func()
0.14236921612231157

但是下面的方法不起作用,因为你必须从import语句中访问隐藏在函数本地范围内的变量:

def func():
    s1 = 'abc'
    s2 = 'abc'
    return timeit.timeit('s1==s2', 'from __main__ import ' + ', '.join(locals()))

但是因为你可以简单地将函数传递给timeit,你可以做的是:

def func(s1='abc', s2='abc'):
    s1 == s2

和

>>> timeit.timeit(func)
0.14399981498718262

所以这也意味着,在你的函数中,你可以提供一个lambda闭包时间:

def func():
    s1 = 'abc'
    s2 = 'abc'
    return timeit.timeit(lambda: s1 == s2)

或者全功能def:

def func():
    s1 = 'abc'
    s2 = 'abc'
    def closure():
        return s1 == s2
    return timeit.timeit(closure)

而且我认为这只是你所要求的.

>>> func()
0.12512516975402832

当他们都不在主程序中时

如果你想用一个设置加入全局变量,而不是从其他模块加入__main__,请使用:

'from ' + __name__ + ' import ' + ', '.join(globals())