Merge two 2d arrays then sort rows by date value which may been found in one of two columns

I have two arrays.

$array1 = [
    [
        'date' => '2012-01-10',
        'result' => 65,
        'name' => 'Les océans',
    ],
    [
        'date' => '2012-01-11',
        'result' => 75,
        'name' => 'Les mers',
    ],
    [
        'date' => '2012-01-13',
        'result' => 66,
        'name' => 'Les continents',
        'type' => 'Scores',
    ]
];

$array2 = [
    [
        'date_end' => '2012-01-12',
        'result' => 60,
        'name' => 'Step#1',
        'type' => 'Summary',
    ]
];

And I want this for my final result:

Array
(
    [0] => Array
    (
        [date] => 2012-01-10
        [result] => 65
        [name] => Les océans
    )
    [1] => Array
    (
        [date] => 2012-01-11
        [result] => 75
        [name] => Les mers
    )
    [2] => Array
    (
        [date_end] => 2012-01-12
        [result] => 60
        [name] => Step#1
        [type] => Summary
    )
    [3] => Array
    (
        [date] => 2012-01-13
        [result] => 66
        [name] => Les continents
        [type] => Scores
    )
)

I need to merge my first array with the second then I want to order this new array by date.

Solution

array_merge and usort is your friend.

function cmp($a, $b){
    $ad = strtotime($a['date']);
    $bd = strtotime($b['date']);
    return ($ad-$bd);
}
$arr = array_merge($array1, $array2);
usort($arr, 'cmp');

Result: (online demo)

Warning: Undefined array key "date"

Deprecated: strtotime(): Passing null to parameter #1 ($datetime) of type string is deprecated

Warning: Undefined array key "date"

Deprecated: strtotime(): Passing null to parameter #1 ($datetime) of type string is deprecated

Warning: Undefined array key "date"

Deprecated: strtotime(): Passing null to parameter #1 ($datetime) of type string is deprecated
array (
  0 => 
  array (
    'date_end' => '2012-01-12',
    'result' => 60,
    'name' => 'Step#1',
    'type' => 'Summary',
  ),
  1 => 
  array (
    'date' => '2012-01-10',
    'result' => 65,
    'name' => 'Les océans',
  ),
  2 => 
  array (
    'date' => '2012-01-11',
    'result' => 75,
    'name' => 'Les mers',
  ),
  3 => 
  array (
    'date' => '2012-01-13',
    'result' => 66,
    'name' => 'Les continents',
    'type' => 'Scores',
  ),
)