Creating a Python list from a list of tuples -

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if have, example, list of tuples such as

a = [(1,2)] * 4

how create list of first element of each tuple? is, [1, 1, 1, 1].

use list comprehension:

>>> = [(1,2)] * 4 >>> [t[0] t in a] [1, 1, 1, 1]

you can unpack tuple:

>>> [first first,second in a] [1, 1, 1, 1]

if want fancy, combine map , operator.itemgetter. in python 3, you'll have wrap construct in list list instead of iterable:

>>> import operator >>> map(operator.itemgetter(0), a) <map object @ 0x7f3971029290> >>> list(map(operator.itemgetter(0), a)) [1, 1, 1, 1]

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