Get list of tuples from nested list

Question

How do I get tuples from nested list of tuples? Here is what I tried:

from itertools import chain
l = [[[('key1', b'val1', b'val1.2'),[('key2', b'val2'),('key3', b'val3'),('key4', b'val4')]]]]
l2 = list(chain.from_iterable(l)) # tried
print(l2)

[[('key1', b'val1', b'val1.2'), [('key2', b'val2'), ('key3', b'val3'), ('key4', b'val4')]]]

Need output like this one:

[('key1', b'val1', b'val1.2'),('key2', b'val2'),('key3', b'val3'),('key4', b'val4')]

Duplicate of https://stackoverflow.com/questions/952914/how-to-make-a-flat-list-out-of-list-of-lists ? — Kyle Willmon, May 06 '19 at 19:51
@KyleWillmon I looked at this post a while ago and tried. It didn't work for my given data — sharp, May 06 '19 at 19:54

Dennis · Accepted Answer · 2019-05-06T19:59:17.250

0

Try this recursive generator:

l = [[[('key1', b'val1', b'val1.2'),[('key2', b'val2'),('key3', b'val3'),('key4', b'val4')]]]]

def all_tuples(nested):
    for item in nested:
        if isinstance(item, list):
            yield from all_tuples(item)
        else:
            assert isinstance(item, tuple)
            yield item

print(list(all_tuples(l)))
# [('key1', b'val1', b'val1.2'), ('key2', b'val2'), ('key3', b'val3'), ('key4', b'val4')]

edited May 06 '19 at 19:59

answered May 06 '19 at 19:55

Dennis

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12

Thanks. What does yeild from do? – sharp May 06 '19 at 20:48
You can think of `yield from a()` as meaning `for x in a(): yield x`. There are some nuances, like how it handles exceptions and `send` statements for coroutines, but that is really all that it means in this case. – Dennis May 07 '19 at 00:23

Get list of tuples from nested list

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