NameError: global name 'reduce' is not defined

问题

I'm new to Python. Would you please tell me what's wrong with the following code? When I run it, I got an error message of "NameError: global name 'reduce' is not defined". I asked Goolge but it's useless. :(

def main():
    def add(x,y): return x+y
    reduce(add, range(1, 11))

if __name__=='__main__':
    main()

回答1:

I'm going to guess that:

1. You are using Python 3, and
2. You are following a tutorial designed for Python 2.

The reduce function, since it is not commonly used, was removed from the built-in functions in Python 3. It is still available in the functools module, so you can do:

import functools

def main():
    def add(x,y): return x+y
    functools.reduce(add, range(1, 11))

回答2:

Also

# Import reduce from functools
from functools import reduce

Allows you to use reduce as though it were a built in function.

def main():
    def add(x,y): return x+y
    reduce(add, range(1, 11))

来源：https://stackoverflow.com/questions/10226381/nameerror-global-name-reduce-is-not-defined