Get the index of the sublist when checking for the existence of an element

Question

As a continuation for this question, how can I get the index of the sublist which contains the element?

So for example if I have:

a = [[1,2],[3,4],[5,6]]
any(2 in i for i in a)
....

How can I get 0 as a result (Because a[0] contains the number 2)?

@OlvinRoght Great! But what if I have the same value (e.g 2) in multiple sublists? This solution gives only the first occurrence it seems. — Madno, Jan 18 '21 at 19:43
Then use list comprehension: `[i for i, el in enumerate(a) if 2 in el]` — Olvin Roght, Jan 18 '21 at 19:44

score 1 · Answer 1 · edited Jan 18 '21 at 19:45

1

Alternatively, you can try this too:

for idx, sublst in enumerate(a):
    if 2 in sublst: 
        print(idx)

Output:

edited Jan 18 '21 at 19:45

Olvin Roght

answered Jan 18 '21 at 19:42

Daniel Hao

score 1 · Accepted Answer · answered Jan 18 '21 at 19:46

Simple list comprehension which iterates over list with indexes using enumerate() will do the trick:

res = [i for i, el in enumerate(a) if 2 in el]

You can achieve same using regular for loop:

res = []
for i, el in enumerate(a):
    if 2 in el:
        res.append(el)

2 Answers2