[
1 => ['id' => 1, 'sort' => 1],
3 => ['id' => 3, 'sort' => 3],
2 => ['id' => 2, 'sort' => 2],
]
How do I sort it so that it's re-ordered using the inner 'sort' key? Desired result:
[
1 => ['id' => 1, 'sort' => 1],
2 => ['id' => 2, 'sort' => 2],
3 => ['id' => 3, 'sort' => 3],
]
You can use usort with this comparison function:
function cmpBySort($a, $b) {
return $a['sort'] - $b['sort'];
}
usort($arr, 'cmpBySort');
Or you use array_multisort with an additional array of key values for the sort order:
$keys = array_map(function($val) { return $val['sort']; }, $arr);
array_multisort($keys, $arr);
Here array_map with the anonymous function is used to build an array of the sort values that is used to sort the array values itself. The advantage of this is that there is np comparison function that needs to be called for each pair of values.
SORT_DESC flag as the parameter between the two parameters of array_multisort() in Gumbo's answer.Something like this:
usort($array, function (array $a, array $b) { return $a["sort"] - $b["sort"]; });
Something like this:
uasort($array, 'compfunc');
function compfunc($a, $b)
{
return $a['sort'] - $b['sort'];
}
Implement the latest syntax (since PHP7.4) use array function syntax with the spaceship operator. Writing $a on the left and $b on the right gives an ASC sort. Conversely $b <=> $a gives a DESC sort.
uasort() preserves the original first level keys (which usort() will not do and array_multisort() will not do with numeric keys).
Code: (Demo)
$array = [
1 => ['id' => 1, 'sort' => 1],
3 => ['id' => 3, 'sort' => 3],
2 => ['id' => 2, 'sort' => 2],
];
uasort($array, fn($a, $b) => $a['sort'] <=> $b['sort']);
var_export($array);