python - Inserting an element before each element of a list -


i'm looking insert constant element before each of existing element of list, i.e. go from:

['foo', 'bar', 'baz']

to:

['a', 'foo', 'a', 'bar', 'a', 'baz']

i've tried using list comprehensions best thing can achieve array of arrays using statement:

[['a', elt] elt in stuff]

which results in this:

[['a', 'foo'], ['a', 'bar'], ['a', 'baz']]

so not want. can achieved using list comprehension? in case matters, i'm using python 3.5.

add loop:

[v elt in stuff v in ('a', elt)]

or use itertools.chain.from_iterable() zip() , itertools.repeat() if need iterable version rather full list:

from itertools import chain, repeat try:     # python 3 version (itertools.izip)     future_builtins import zip except importerror:     # no import needed in python 3  = chain.from_iterable(zip(repeat('a'), stuff))

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