Question

When I try this code in Python 3.x, I get an error message that says "NameError: global name ‘reduce’ is not defined".

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

if __name__=='__main__':
    main()

Why?

Answer 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))