built-in-rules-each.md

Each - applying the same rules for each data item in the set

The Each rule allows the same rules to be applied to each data item in the set. The following example shows the configuration for validating RGB color components:

use Yiisoft\Validator\Rule\Each;
use Yiisoft\Validator\Rule\Integer;

new Each([
    new Integer(min: 0, max: 255),
]);

By combining with another built-in rule called Count we can be sure that the number of components is exactly 3:

use Yiisoft\Validator\Rule\Count;
use Yiisoft\Validator\Rule\Each;
use Yiisoft\Validator\Rule\Integer;

$rules = [
    // Applies to a whole set.
    new Count(3),
    // Applies to individual set items.
    new Each(        
        // For single rules, wrapping with array / iterable is not necessary.
        new Integer(min: 0, max: 255),
    ),
];

Validated data items are not limited to only "simple" values - Each can be used both within a Nested and contain Nested rule covering one-to-many and many-to-many relations:

use Yiisoft\Validator\Rule\Count;
use Yiisoft\Validator\Rule\Each;
use Yiisoft\Validator\Rule\Nested;
use Yiisoft\Validator\Rule\Number;

$rule = new Nested([
    'charts' => new Each([
        new Nested([
            'points' => new Each([
                new Nested([
                    'coordinates' => new Nested([
                        'x' => [new Number(min: -10, max: 10)],
                        'y' => [new Number(min: -10, max: 10)],
                    ]),
                    'rgb' => new Each([
                        new Count(3),
                        new Number(min: 0, max: 255),
                    ]),
                ]),
            ]),
        ]),
    ]),
]);

For more information about using it with Nested, see the Nested guide.