Question

This code is perfectly valid Python

x=[[1,2,3,4], [11,22,33,44]]
for e in x:
    for e in e:
        print e

Can someone please tell me why, and how this works?

I understand that both the e‘s are in different scopes, but how come using them together like this isn’t causing an error?

Answer 1

The scopes aren’t different; in Python a function has a single local scope (as does code entered at global level in the console).

The reason the code is OK is that you finish using the outer value of e before you rebind it to the inner values; try looking at what this prints:

x=[[1,2,3,4], [11,22,33,44]]
for e in x:
    for e in e:
        print e
    print e