Like array_unique, but the uniqueness test is a callback that returns the key to dedupe by. Useful for "unique by ID" or "unique by lowercased email" across arrays of objects/rows.
PHP
<?php
function uniqueBy(array $items, callable $keyFn): array {
$seen = [];
$out = [];
foreach ($items as $item) {
$k = $keyFn($item);
if (!array_key_exists($k, $seen)) {
$seen[$k] = true;
$out[] = $item;
}
}
return $out;
}
$users = [
['id'=>1,'name'=>'Alice'],
['id'=>2,'name'=>'Bob'],
['id'=>1,'name'=>'Alice (dup)'],
];
print_r(uniqueBy($users, fn($u) => $u['id']));
// [ {id:1,name:Alice}, {id:2,name:Bob} ]Save your own code snippets
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