Hi
Am 2026-02-22 19:58, schrieb Muhammed Arshid KV:
Here is a simple example of an `array_only()` implementation using
existing
PHP functions:
```php
function array_only(array $input, array $keys): array {
return array_intersect_key($input, array_flip($keys));
}
```
This works, but `array_flip($keys)` creates an extra temporary hash
table.
So peak memory becomes: input + keys + flipped array + result.
That is true for this specific implementation of a “wrapper function”.
It is not necessarily true for other implementations, e.g. simply using
the functions directly instead of creating a wrapper for two method
calls. `array_flip()` supports compile-time evaluation, so you can just
write:
$dataWithOnlyIdAndEmail = \array_intersect_key($data,
\array_flip(['id', 'email']));
and OPcache will make sure to rewrite it to:
$dataWithOnlyIdAndEmail = \array_intersect_key($data, ['id' => 0,
'email' => 1]);
avoiding the intermediate array.
Best regards
Tim Düsterhus
PS: It appears that the RFC is not listed in the overview at
https://wiki.php.net/rfc.
