How to get first elements of each list in a list of lists

Question

i need help working on a list: i have a list like this

[[1, 2, 3, 5], [3, 4, 5, 6], [7, 8, 9, 3],[10, 11, 12, 13]]

how do I get the first element of all the list within the list.

desired output:

```output = [lst[0] for lst in input_list]``` – shivankgtm Jan 27 '22 at 07:47 — shivankgtm, Jan 27 '22 at 07:47

score 1 · Accepted Answer · answered Jan 27 '22 at 07:50

1

You just iterate as it were a flat list

lists = [[1, 2, 3, 5], [3, 4, 5, 6], [7, 8, 9, 3],[10, 11, 12, 13]]
 
for l in lists:
   if l != []:
     print(l[0])

answered Jan 27 '22 at 07:50

radrow

thank you, do you have an idea, how i can put the out put in a list or array like ['1', '3', '7', '10'] or {'1' , '3', '7', '10'} – Noble somto Jan 27 '22 at 08:13
1

@Noblesomto initialize a list with ```firsts = []``` before the for loop and replace the print statement in the code with ```firsts.append(l[0])``` – felix Jan 27 '22 at 08:20

1 Answers1