Rearrange 2-dimensional array dynamically

Question

how to dynamically convert this type of array:

[
    [a,b,c],
    [d,e,f],
]

into

[
    [a,d],
    [b,e],
    [c,f],
]

the length of the first array is not always the same size.

tried the following

for (var i = 0; i < multi.length; i++) { // 2
    for (var j = 0; j < multi[i].length; j++) { // 3
        multi2[j].push(multi[j][i])
    }
}

it does not work

Try a Google search for array **transposition** in JavaScript. — Simon Kuang, Jul 01 '14 at 02:05
The outer loop should iterate `arr[0].length` times, while the inner loop iterates `arr.length` times. — Ja͢ck, Jul 01 '14 at 02:10

cbayram · Answer 1 · 2014-07-01T02:40:50.137

-1

Two issues:

Initialize your multi2 subarray for i.
You have your i and j mixed up in the inner loop.

Here's a fiddle

var multi = [
  ["a","b","c"],
  ["d","e","f"],
  ["g","h","i"],
]
var multi2 = [];

for (var i = 0; i < multi.length; i++) { // 3
  for (var j = 0; j < multi[i].length; j++) { // 3
    multi2[j] = multi2[j]||[]; // initialize subarray if necessary
    multi2[j].push(multi[i][j])
  }
}

edited Jul 01 '14 at 02:40

answered Jul 01 '14 at 02:06

cbayram

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Rearrange 2-dimensional array dynamically

1 Answers1