I have a 3d list
aa = [[[2, 3, 4, 5],
[ 6, 7, 8, 9]], [[11, 12, 14, 15]]], which consists of two 2d lists
how do I get this result
[[2, 6], [11]]
the first element of each sub list.
b = [] for i, row in enumerate(aa): for j, rr in enumerate(row): b.append(rr[0])
gives
[2,6,11]
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Answer
You can do it with a list comprehension:
[[i[0] for i in j] for j in aa]
Output:
[[2, 6], [11]]