Foreach() Skips Uninitialized Properties¶

<?php

class z {
    public readonly int $p;
    public readonly int $q;

    public function __construct()
    {
        $this->p = 1;
    }
}

$x = new z;

// foreach skips undefined properties, readonly or not
foreach($x as $k => $v) {
    print $k . " " . $v . PHP_EOL;
}

echo $x->q;
?>

Foreach() reads naturally all public properties in an object. Protected and private are omitted, unless in the right context.

Foreach() also skips silently uninitialized properties: this prevents the generation of NULL values, but also, skips all readonly properties: any direct hit on such property would otherwise generate a Fatal error.

See Also¶

Foreach (PHP manual)
foreach skips the empty values [Try me]

PHP Features¶

Last updated: 14 July 2026