I don't understand the operation here: for index, item in enumerate(choices):

Question

I'm currently learning Python through Codecademy. One of the exercises uses this in it's for loop:

choices = ['pizza', 'pasta', 'salad', 'nachos']

print 'Your choices are:'
for index, item in enumerate(choices):
    print index + 1, item

I've only seen things like:

for i in list:

That being said, I don't understand what the "index," part of the loop is, or what it's function is. All I understand from this is that it will index each item in the list, and print them. Thanks in advance.

Answer 1

Enumerate makes a list of tuple which are (index, element).

l = ['thing', 'foo', 'bar', 'doodad']
list(enumerate(l))

This is the output of enumerate

[(0, 'thing'), (1, 'foo'), (2, 'bar'), (3, 'doodad')]

You can unpack these tuples and do whatever you'd like with each component of the tuple.

for index, element in enumerate(l):
    print 'index', index
    print 'element', element

index 0
element thing

index 1
element foo

index 2
element bar

index 3
element doodad