Online PHP editor | output for XVBZm

@ 2020-06-18T03:38:23Z

<?php

$array = [
    ['date' => '2017-08-22', 'AAA' => 1231],
    ['date' => '2017-08-21', 'AAA' => 1172],
    ['date' => '2017-08-20', 'AAA' => 1125],
    ['date' => '2017-08-21', 'BBB' => 251],
    ['date' => '2017-08-20', 'BBB' => 21773],
    ['date' => '2017-08-22', 'CCC' => 3750],
    ['date' => '2017-08-20', 'CCC' => 321750],
];

foreach ($array as $row) {
    $date = $row['date'];
    unset($row['date']);
    $result[$date] = array_merge($result[$date] ?? [], $row);
}
var_export($result);

Output for 7.0.0, 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.27, 8.4.1 - 8.4.14: array ( '2017-08-22' => array ( 'AAA' => 1231, 'CCC' => 3750, ), '2017-08-21' => array ( 'AAA' => 1172, 'BBB' => 251, ), '2017-08-20' => array ( 'AAA' => 1125, 'BBB' => 21773, 'CCC' => 321750, ), )
Output for 5.4.24, 5.6.13 - 5.6.40: Parse error: syntax error, unexpected '?' in /in/XVBZm on line 16
Process exited with code 255.
Output for 4.3.0: Parse error: parse error, unexpected '[' in /in/XVBZm on line 3
Process exited with code 255.

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