convert arrays to python list of lists

Question

New to python and can't figure this out:

I am importing data from a cloud data warehouse into Python. This is the resulting data structure:

[('A,B',),
 ('A',),
 ('A,B,C',)]

How can I convert the data into this format:

[['A','B'],
 ['A'],
 ['A','B','C']]

[list(x[0].replace(',','')) for x in lst]... although this feels like the kind of conversion that you shouldn't have to do (like there should be a better way to retrieve/parse the data) — Chris_Rands
– Chris_Rands, Commented Aug 16, 2018 at 14:50
This looks like you were given a CSV file and parsed it wrong, and now you want to reorganize what you misparsed, instead of just parsing it right in the first place. Please show us the code that you used to get this data structure and we can probably should you how to fix that code instead. — abarnert
– abarnert, Commented Aug 16, 2018 at 15:24

Laurent H. · Accepted Answer · 2018-08-16 15:15:59Z

2

I suggest you the following way using a list comprehension to iterate over the list and over each tuple:

my_list = [('A,B',), ('A',), ('A,B,C',)]

new_list = [s.split(',') for t in my_list for s in t]

print(new_list) # [['A', 'B'], ['A'], ['A', 'B', 'C']]

If there is always one string as first element of each tuple, then you could also use the following, which is shorter and more readable:

new_list = [t[0].split(',') for t in my_list]

A last possibility reserved to the lovers of unpacking operator:

new_list = [str(*t).split(',') for t in my_list]

edited Aug 16, 2018 at 15:15

answered Aug 16, 2018 at 15:02

Laurent H.

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Comments

Somesh · Accepted Answer · 2018-08-16 14:59:17Z

0

my_list = [('A,B',), ('A',), ('A,B,C',)]

new_list = [list(items) for items in my_list]

output :

[['A', 'B'], ['A'], ['A', 'B', 'C']]

answered Aug 16, 2018 at 14:59

Somesh

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2 Comments

jpp Over a year ago

This is incorrect. There is no string splitting, or comma replacement applied.

Laurent H. Over a year ago

It does not work: it gives [['A,B'], ['A'], ['A,B,C']]

Arghya Saha · Accepted Answer · 2018-08-16 15:17:07Z

0

This one liner can solve your problem:

data = [('A,B',), ('A',), ('A,B,C',)]

final_data = [list(list(item)[0].split(',')) for item in data]
print(final_data)

answered Aug 16, 2018 at 15:17

Arghya Saha

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