Transpose an associative array containing indexed elements

Question

I've got an array which looks like this:

array(3) {
  ["title"]=>
  array(3) {
    [0]=>
    string(3) "one"
    [1]=>
    string(3) "two"
    [2]=>
    string(4) "test"
  }
  ["file"]=>
  array(3) {
    [0]=>
    string(25) "company_handbook_2011.pdf"
    [1]=>
    string(8) "test.doc"
    [2]=>
    string(8) "test.doc"
  }
  ["status"]=>
  array(3) {
    [0]=>
    string(4) "SHOW"
    [1]=>
    string(4) "HIDE"
    [2]=>
    string(4) "HIDE"
  }
}

how can i rearrange it to look like this:

array(
    array(
        "one",
        "company_handbook_2011.pdf",
        "SHOW"
    ),
    array(
        "two",
        "test.doc",
        "HIDE"
    ),
    array(
        "test",
        "test.doc",
        "HIDE"
    ),      
)

i.e get the first element of each array and and build a new array and then the second element and so on. Thank very much for your help.

There's no ready-made function for this I think. You'll have to simply walk through the array in a loop, and build it — Pekka, Apr 07 '11 at 15:41
You don't necessarly have to walk through the array since the indexes seem to match between your different keys. You could count the number `$array['title']` and then use a simple for loop that gets the values from the right positions to construct a new array. Would be interesting to benchmark which method is faster. — Capsule, Apr 07 '11 at 15:44
some useful information from you guys thanks very much...appreciate your time. array_map did the job. — bharath, Apr 07 '11 at 15:56

score 3 · Accepted Answer · edited May 23 '17 at 09:58

What you are searching for is called the transpose of a matrix. Here is a previous answer on StackOverflow:

Is there better way to transpose a PHP 2D array?

I take the liberty to directly copy the solution from that thread ($array_of_arrays is your original array, $transposed_array is the result):

$transposed_array = call_user_func_array('array_map', array_merge(array(NULL), $array_of_arrays));

score 0 · Answer 2 · answered Apr 07 '11 at 15:43

0

foreach ($origArray['title'] as $k => $title) {
    $flatArr[] = array($title, $origArray['file'][$k], $origArray['status'][$k]);
}

answered Apr 07 '11 at 15:43

vartec

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Transpose an associative array containing indexed elements

2 Answers2