Restructure multidimensional array of column data into multidimensional array of row data

Question

I have the following associative array of column data:

$where = array(
    'id'=>array(
        12,
        13,
        14
    ),
    'date'=>array(
        '1999-06-12',
        '2000-03-21',
        '2006-09-31'
    )
);

I need to transpose / rotate the structure to be an array of rows (with merged column data assigned to their respective row). I don't need the column names in the result.

Expected output:

$comb = array(
    array(12, '1999-06-12'),
    array(13, '2000-03-21'),
    array(14, '2006-09-31')
);

Answer 1

Solution 1: Hope this simple foreach to get the desired result

Try this code snippet here

<?php
ini_set('display_errors', 1);
$where = array('id'=>array(12,13,14),'date'=>array('1999-06-12','2000-03-21','2006-09-31'));

$result=array();
foreach($where["id"] as $key => $value)
{
    $result[]=array($value,$where["date"][$key]);
}

Solution 2: Here we are using array_walk to achieve the same result

Try this code snippet here

<?php
ini_set('display_errors', 1);
$result=array();
$where = array('id'=>array(12,13,14),'date'=>array('1999-06-12','2000-03-21','2006-09-31'));

array_walk($where["id"], function($value,$key) use(&$result,&$where){
    $result[]=array($value,$where["date"][$key]);
});
print_r($result);

Solution 3: Here we are using array_shift on $where["date"].

Try this code snippet here

<?php
ini_set('display_errors', 1);
$result=array();
$where = array('id'=>array(12,13,14),'date'=>array('1999-06-12','2000-03-21','2006-09-31'));

foreach($where["id"] as $value)
{   
    $result[]=array($value,  array_shift($where["date"]));
}
print_r($result);

Answer 2

As Kris Roofe stated in his deleted answer, array_column is indeed a more elegant way. Just be sure to put it into some kind of a foreach loop, similar to what Sahil Gulati showed you. For example, like this:

$result = array();

foreach($where['id'] as $k => $v)
{
  $result[] = array_column($where, $k);
}

The var_dump output of $result is exactly what you're looking for

array(3) {
  [0]=>
  array(2) {
    [0]=>
    int(12)
    [1]=>
    string(10) "1999-06-12"
  }
  [1]=>
  array(2) {
    [0]=>
    int(13)
    [1]=>
    string(10) "2000-03-21"
  }
  [2]=>
  array(2) {
    [0]=>
    int(14)
    [1]=>
    string(10) "2006-09-31"
  }
}

Answer 3

I've completely re-written my answer because it was unnecessarily bloating this page. Truth is, there is a very clean and native way to handle this specific task of "transposing". Using null as the function argument and passing in the two known rows from the input array is all that is required.

Code: (Demo)

$where = [
    'id' => [12, 13, 14],
    'date' => ['1999-06-12', '2000-03-21', '2006-09-31']
];

var_export(
    array_map(null, $where['id'], $where['date'])
);

Output:

array (
  0 => 
  array (
    0 => 12,
    1 => '1999-06-12',
  ),
  1 => 
  array (
    0 => 13,
    1 => '2000-03-21',
  ),
  2 => 
  array (
    0 => 14,
    1 => '2006-09-31',
  ),
)

For anyone that truly needs a dynamic solution (because the number of rows may fluxuate/change and you don't want to keep maintaining the processing code), then I recommend that you check the version history of my answer.