Two helpful functions

zip

Suppose you have two lists:

ids = ['a', 'b', 'c', 'd']
fruits = ['apples', 'bananas', 'oranges', 'grapes']
for c in zip(ids, fruits):
    print(c)

('a', 'apples')
('b', 'bananas')
('c', 'oranges')
('d', 'grapes')

enumerate

suppose you had a single list:

fruits = ['apples', 'bananas', 'oranges', 'grapes']
for i, f in enumerate(fruits):
    print("%d: the fruit is %s" % (i,f))

0: the fruit is apples
1: the fruit is bananas
2: the fruit is oranges
3: the fruit is grapes