Keep empty list in the same index, while flattening a list ot list (nested list)

Question

I have a list of lists like this,

sm = [['123'],['456'],['789'],[],['101']]

then I flatten the list,

sm_flattened = [val for sublist in sm for val in sublist]

Now, I get this (sm_flattened),

['123', '456', '789', '101']

However, I need my sm_flattened like this,

['123', '456', '789', '', '101']

How can I get this? Any suggestions would be nice!

Guilherme Sehn · Accepted Answer · 2018-10-26 20:30:55Z

4

In order to do that, you'll need to transform your empty sublist in a sublist with an empty string inside.

One alternative would be:

sm_flattened = [val for sublist in sm for val in (sublist or [''])]

It basically uses [''] instead of sublist in case sublist is empty for that iteration.

answered Oct 26, 2018 at 20:30

Guilherme Sehn

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