duplication in list comprehension

[Mekire]

Well, like this I guess:

x = ['a','b','c','d','e','f']

doubles = [item for pair in zip(x,x) for item in pair]

print(doubles)

But do you really think that is clearer than this:

doubles = []
for item in x:
    doubles.extend([item]*2)

print(doubles)

Matter of taste I guess.  Honestly not sure which I prefer.

Also, this I guess:

import itertools


x = ['a','b','c','d','e','f']
doubles = list(itertools.chain(*zip(x, x)))
print(doubles)

Basically it is a list flattening problem.
Lots of stuff here:
http://stackoverflow.com/questions/95291...-in-python