Translating Python loop to Javascript

Question

How can I yield the same output in Javascript, given this Python example?

I want to loop over an array and check a value, if condition met, store it.

arr1 = [ 0,  0,  0,  0,  0,  0,  0,  0,  0,  7,  7,  0,  0,  0,  0,  0,  0,  0,
        13, 13,  0,  0,  0,  0,  0,  0,  0,  0, 13, 13,  0,  0,  0,  0,  0,  0,
         0,  0,  0, 15,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 14,  0,  0,
         0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  2,  0,
         0,  0]

new_labels = []
previous = None
for l in arr1:
    if l != previous:
        new_labels.append(l)
        previous = l

# expected: 
[0, 7, 0, 13, 0, 13, 0, 15, 0, 14, 0, 2, 0]

Asked By: John Stud

||

Source

Answer 1

This can be done more simply with Array#filter.

let arr1 = [ 0,  0,  0,  0,  0,  0,  0,  0,  0,  7,  7,  0,  0,  0,  0,  0,  0,  0,13, 13,  0,  0,  0,  0,  0,  0,  0,  0, 13, 13,  0,  0,  0,  0,  0,  0,0,  0,  0, 15,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 14,  0,  0,0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  2,  0,0,  0];
let res = arr1.filter((x, i) => x !== arr1[i - 1]);
console.log(JSON.stringify(res));

Answered By: Unmitigated

Translating Python loop to Javascript

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