Turn a list of single tuples into a list without tuples

Question

I'm working with lists of single tuples that looks like this:

data = [[('jog',), ('Jim',), ('jell',), ('jig',)], [('jabs',), ('jilt',), ('job',), ('jet',)]]

Notice that the list contains two elements: two lists containing 4 tuples. Basically, I'm just trying to remove each tuple and make it look like this:

data = [['jog','Jim','jell','jig'], ['jabs','jilt','job','jet']]

I think this can probably be done with list comprehension, but I've tried for hours and can't come up with the magic formula. Can anyone help with this?

Answer 1

The listcomp "magic formula" you're looking for is best done with a nested listcomp using unpacking in the innermost listcomp:

data = [[x for [x] in sublist] for sublist in data]

The [x] there triggers the unpacking of the single element tuple in the most efficient manner possible (while also verifying it is in fact exactly one element per tuple , no more, no less). Otherwise it's a largely no-op nested listcomp.

Answer 2

Use list comprehension like so:

data = [[('jog',), ('Jim',), ('jell',), ('jig',)], [('jabs',), ('jilt',), ('job',), ('jet',)]]
data = [[tup[0] for tup in lst] for lst in data]
print(data)
# [['jog', 'Jim', 'jell', 'jig'], ['jabs', 'jilt', 'job', 'jet']]

Answer 3

If you want to flatten your tuples in a list, you can use itertools.chain :

import itertools

data = [[('jog',), ('Jim',), ('jell',), ('jig',)], [('jabs',), ('jilt',), ('job',), ('jet',)]]

result = [list(itertools.chain(*d)) for d in data]

# result = [['jog', 'Jim', 'jell', 'jig'], ['jabs', 'jilt', 'job', 'jet']]