获取“未定义全局名称'foo'"；用Python的timeit [英] Getting "global name 'foo' is not defined" with Python's timeit

问题描述

我试图找出执行一条Python语句要花费多少时间，所以我上网查看了一下，发现标准库提供了一个名为

I'm trying to find out how much time it takes to execute a Python statement, so I looked online and found that the standard library provides a module called timeit that purports to do exactly that:

import timeit

def foo():
    # ... contains code I want to time ...

def dotime():
    t = timeit.Timer("foo()")
    time = t.timeit(1)
    print "took %fs\n" % (time,)

dotime()

但是，这会产生错误:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in dotime
  File "/usr/local/lib/python2.6/timeit.py", line 193, in timeit
    timing = self.inner(it, self.timer)
  File "<timeit-src>", line 6, in inner
NameError: global name 'foo' is not defined

我还是Python的新手，我还不完全了解它的所有作用域问题，但是我不知道为什么此代码段不起作用.有什么想法吗?

I'm still new to Python and I don't fully understand all the scoping issues it has, but I don't know why this snippet doesn't work. Any thoughts?

推荐答案

更改此行:

t = timeit.Timer("foo()")

对此:

t = timeit.Timer("foo()", "from __main__ import foo")

查看您在底部提供的链接.

Check out the link you provided at the very bottom.

要让timeit模块访问您定义的功能，可以传递一个包含导入语句的设置参数:

To give the timeit module access to functions you define, you can pass a setup parameter which contains an import statement:

我刚刚在机器上对其进行了测试，并且可以进行更改.

I just tested it on my machine and it worked with the changes.

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