Flatten a lists of list with some lists have multiple values - python

Question

I was going through this post, which has some great answers, but it does not work for my situation.

I have a list like this:

my_list = [['Hi'],['Hello'],['How', 'are'], ['you']]

I did the flattening and I am getting this,

my_flat_list = [i[0] for i in my_list]
my_flat_list
>>['Hi', 'Hello', 'How', 'you']

If I don't use i[0] I get in list format again.

The output I need is:

['Hi', 'Hello', 'How are', 'you']

I also tired this post using itertools still not getting my desired results.

How can I get my output?

@DyZ Question, how did you search that SO post? I have been Googling, did not find any related to my situation, then I posted this question. Is there a trick? May be always use a keyword involved? or anything else? — user9431057, Jul 06 '18 at 21:46
@user9431057 I found that dupe by googling "How to join sublists of strings in python". While yes, this ends up flattening the list, most list flattening questions don't join elements of the sublists, which is why you wouldn't have been able to find it. — user3483203, Jul 06 '18 at 21:49
@user3483203 Okay, in the beginning I had no idea that it needs a join. I have been googling 'how to flatten lists' :(. Thank for the comment, love to learn with you all :) — user9431057, Jul 06 '18 at 21:51
Happy to help. You asked a good question with all the necessary information, so keep it up! — user3483203, Jul 06 '18 at 21:53
There are two steps to the problem, and each is a common duplicate. `' '.join` can join a list of strings; apply that to each list in the list of lists. — Karl Knechtel, Sep 06 '22 at 04:50

score 2 · Answer 1 · answered Jul 06 '18 at 21:39

2

You need to join the inner lists:

list(map(" ".join, my_list))
#['Hi', 'Hello', 'How are', 'you']

answered Jul 06 '18 at 21:39

DYZ

score 1 · Accepted Answer · answered Jul 06 '18 at 21:39

1

str.join will help you turn every sublist to a single string:

In [1]: [' '.join(sublist) for sublist in my_list]
Out[1]: ['Hi', 'Hello', 'How are', 'you']

answered Jul 06 '18 at 21:39

Eugene Primako

2 Answers2