Get first element of each array in a parent array

Question

I have an array of arrays in TypesScript and I want to splice it to get the first element of each sub-array. This isn't that hard of a task but I want a concise way of doing it.

Here is a Python example of what I want in TypeScript:

l1 = [[1,2],[3,4],[5,6]]
l2 = [i[0] for i in l1]
print(l2) # [1, 3, 5]

Did you look at map() ? You want more concise than that?

Tushar Shahi
– Tushar Shahi

2022-11-08 18:43:44 +00:00
Commented Nov 8, 2022 at 18:43 — Tushar Shahi
– Tushar Shahi, Commented Nov 8, 2022 at 18:43

Alexander · Accepted Answer · 2022-11-08 21:26:28Z

2

You would use map to transform each sub-array, passing it a function that takes a sub-array and returns its first element:

const input = [[1, 2], [3, 4], [5, 6]]
const output = input.map(subarray => subarray[0])
console.log(output) // => [1, 3, 5]

edited Nov 8, 2022 at 21:26

answered Nov 8, 2022 at 18:44

Alexander

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