Using enumerate to retrieve item and index in iterable

This article shows how you can use enumerate to extract letters from a word and group all letters and calculate a list of indexes where they are used.

#Goal: Build a map of indexes for all tokens in the string
from collections import defaultdict 

text = 'robby pelssers'
d = defaultdict(list)
for index, letter in ((index, letter) for index, letter in enumerate(text)):
    d[letter].append(index)

for item in d.items():
    print item

(' ', [5])
('b', [2, 3])
('e', [7, 11])
('l', [8])
('o', [1])
('p', [6])
('s', [9, 10, 13])
('r', [0, 12])
('y', [4])