Get all index from boolean list

Question

I have a problem with a pice of my code. I have a boolean list and need to know which index is true.

lst = [True, True, False]

for element in lst:
 print(lst.index(element))

why the output is 0,0,2?

I just need output 0,1,2

index 2 is "False". Here i'm just printing the index of every element in the list. But the second True should have index 1 but its printing index 0 — Aleksandra Tkaczyk, Mar 10 '22 at 16:12
You're printing the index of element for each element of the list. When element is true, it will return 0 (the first index to be True). When element is false, it will return 2 (the first index to be False). In total, it returns 0, 0, 2. I suggest you check that other post : https://stackoverflow.com/questions/6294179/how-to-find-all-occurrences-of-an-element-in-a-list — Mateo Vial, Mar 10 '22 at 16:12

score 1 · Answer 1 · answered Mar 10 '22 at 16:13

1

Do this.

lst = [True, True, False]

for idx, val in enumerate(lst):
    if val == True:
        print(idx)

The output

0
1

answered Mar 10 '22 at 16:13

Lion Lai

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Since they want an output of `[0,1,2]`, isn't the `if val == true` not helpful? – Bill Lynch Mar 10 '22 at 16:15

score 0 · Answer 2 · answered Mar 10 '22 at 16:09

This will print only the true, so I'm not sure if its exactly what you need. If you provide more context we could probably help get a better answer for your specific problem.

lst = [True, True, False]

for element in lst:
    if element == True:
        print(element)

Get all index from boolean list

2 Answers2