added Arrays::filter()

Author: dg

src/Utils/Arrays.php

@@ -369,6 +369,27 @@ public static function every(iterable $array, callable $predicate): bool
 	}
 
 
+	/**
+	 * Returns a new array containing all key-value pairs matching the given $predicate.
+	 * The callback has the signature `function ($value, $key, $array): bool`.
+	 * @template K of array-key
+	 * @template V
+	 * @param  array<K, V> $array
+	 * @param  callable(V, K, array<K, V>): bool $predicate
+	 * @return array<K, V>
+	 */
+	public static function filter(array $array, callable $predicate): array
+	{
+		$res = [];
+		foreach ($array as $k => $v) {
+			if ($predicate($v, $k, $array)) {
+				$res[$k] = $v;
+			}
+		}
+		return $res;
+	}
+
+
 	/**
 	 * Returns an array containing the original keys and results of applying the given transform function to each element.
 	 * The function has signature `function ($value, $key, $array): mixed`.

tests/Utils/Arrays.filter().phpt

@@ -0,0 +1,42 @@
+<?php
+
+/**
+ * Test: Nette\Utils\Arrays::filter()
+ */
+
+declare(strict_types=1);
+
+use Nette\Utils\Arrays;
+use Tester\Assert;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+Assert::same(
+	['a' => 1, 'b' => 2],
+	Arrays::filter(
+		['a' => 1, 'b' => 2, 'c' => 3],
+		fn($v) => $v < 3,
+	),
+);
+
+Assert::same(
+	['c' => 3],
+	Arrays::filter(
+		['a' => 1, 'b' => 2, 'c' => 3],
+		fn($v, $k) => $k === 'c',
+	),
+);
+
+Assert::same(
+	['a' => 1, 'b' => 2, 'c' => 3],
+	Arrays::filter(
+		['a' => 1, 'b' => 2, 'c' => 3],
+		fn($v, $k, $a) => $a === ['a' => 1, 'b' => 2, 'c' => 3]
+	),
+);
+
+Assert::same(
+	[],
+	Arrays::filter([], fn() => true)
+);