timing a function with timeit? (newbie problem)

[news.west.cox.net]

Why do I get the exception "global name 'test' is not defined" in this code
(next to last line) and how do I fix it?

import timeit
def test():
x=2+2
t = timeit.Timer('test()')
print t.timeit()

 

[Chad Netzer]

Why do I get the exception "global name 'test' is not defined" in this code
(next to last line) and how do I fix it?

import timeit
def test():
x=2+2
t = timeit.Timer('test()')
print t.timeit()

You need to tell it about test() with the setup argument (by either
defining it directly, or importing it.

0.61572694778442383

0.71046602725982666

This is because globals are at the module scope. The timeit module is
separate from the interactive (ie. '__main__') namespace. The Timer
function compiles your code in the namespace where it is defined, not
where it is called. So, it's 'globals' are the globals in the timeit
module, and thus, it cannot see your test() function as a global.