Python find index of list of list, but only at specific index of internal list

Question

I have a list of lists in the format:

list = [["5:2", "1:0"],["3:4", "5:2"],["1:2", "1:1"],["4:5", "1:0"]]

I would like to check if the first index of each internal lists contains a string. I have tried to use the following:

(next(i for i,j in enumerate(list) if (a) in j))

However, this checks every string in the list of lists, instead of a specific index.

How could I modify this code to only check index 0 of the internal list?

Thanks

Answer 1

Two possible solutions:

1. If you want all the list elements' indices that have the first element as a string:

ans = [i for i, j in enumerate(list) if type(j[0]) == str]

2. If you want a boolean output list:

ans = [True if type(i[0]) == str else False for i in list]