Convert a list list into a single list

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9

I’m working on Python 2.7. I have this result:

Resultado=[['A','B','C'],['D','E','F'],['G','H','I']]

How can I turn this into a list? And get the following:

Lista=['A','B','C','D','E','F','G','H','I']

Thank you!

python python-2.7

2 answers

7


To make a single list of:

Resultado=[['A','B','C'],['D','E','F'],['G','H','I']]

Do (no need to import external libs for this, this is what I recommend):

Lista = [item for sublista in Resultado for item in sublista]

Alternatives:

Lista = []
for i in Resultado:
    Lista.extend(i)

print Lista  #['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I']

Or:

Lista = []
[Lista.extend(i) for i in Resultado]

print Lista  #['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I']

4

I would do it using the method chain of itertools

from itertools import chain

Resultado  = [['A','B','C'],['D','E','F'],['G','H','I']]

Lista = list(chain(*Resultado))

print (Lista); # ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I']

Just for more information on how to search if necessary, the name of this operation in English is called flatten. It means you’re turning a multilevel list into a one-dimensional list.

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