How to make an array out of the nth element of items in a 2d array?

Question

Not sure how to google this for the same reason I am not sure how to write the title.

basically if I have the array:

[[1,2,3],[4,5,6],[7,8,9]]

I want to pull say the 2nd(nth) item of each array and turn them into an array as such:

[2,5,8]

What is the quickest (preferably immediate) way to parse the array this way without using for-loops?

Just because you're hiding the loop behind an abstraction does not mean that it is not there @Laif — Henry Ecker, Aug 20 '21 at 01:52
@Laif nope. All the answers here involve loops, even if they might be hidden. — juanpa.arrivillaga, Aug 20 '21 at 04:04

leaf_yakitori · Accepted Answer · 2021-08-20T01:38:55.900

3

x = [[1,2,3],[4,5,6],[7,8,9]]
y = [ele[1] for ele in x]

x = [[1,2,3],[4,5,6],[7,8,9]]
y = list(map(lambda x:x[1],x))

edited Aug 20 '21 at 01:38

answered Aug 20 '21 at 01:35

leaf_yakitori

This is close enough to what I meant I think, I'll mark it answered when I can – Libra Aug 20 '21 at 01:38

score 0 · Answer 2 · answered Aug 20 '21 at 01:36

0

If you don't consider a list comprehension a loop (even though it is certainly looping under the hood), you could accomplish this like:

list1 = [[1,2,3], [4,5,6], [7,8,9]]
list2 = [ e[1] for e in list1 ]

answered Aug 20 '21 at 01:36

Nicholas Hayashi

2 Answers2