added Arrays::mapWithKeys() & Iterables::mapWithKeys()

Author: dg

src/Utils/Arrays.php

@@ -449,6 +449,31 @@ public static function map(iterable $array, callable $transformer): array
 	}
 
 
+	/**
+	 * Returns an array containing new keys and values generated by applying the given transform function to each element.
+	 * If the function returns null, the element is skipped.
+	 * @template K of array-key
+	 * @template V
+	 * @template ResultK of array-key
+	 * @template ResultV
+	 * @param  array<K, V> $array
+	 * @param  callable(V, K, array<K, V>): ?array{ResultK, ResultV} $transformer
+	 * @return array<ResultK, ResultV>
+	 */
+	public static function mapWithKeys(array $array, callable $transformer): array
+	{
+		$res = [];
+		foreach ($array as $k => $v) {
+			$pair = $transformer($v, $k, $array);
+			if ($pair) {
+				$res[$pair[0]] = $pair[1];
+			}
+		}
+
+		return $res;
+	}
+
+
 	/**
 	 * Invokes all callbacks and returns array of results.
 	 * @param  callable[]  $callbacks

src/Utils/Iterables.php

@@ -158,6 +158,27 @@ public static function map(iterable $iterable, callable $transformer): \Generato
 	}
 
 
+	/**
+	 * Iterator that transforms keys and values by calling $transformer. If it returns null, the element is skipped.
+	 * @template K
+	 * @template V
+	 * @template ResultK
+	 * @template ResultV
+	 * @param  iterable<K, V> $iterable
+	 * @param  callable(V, K, iterable<K, V>): ?array{ResultK, ResultV} $transformer
+	 * @return \Generator<ResultK, ResultV>
+	 */
+	public static function mapWithKeys(iterable $iterable, callable $transformer): \Generator
+	{
+		foreach ($iterable as $k => $v) {
+			$pair = $transformer($v, $k, $iterable);
+			if ($pair) {
+				yield $pair[0] => $pair[1];
+			}
+		}
+	}
+
+
 	/**
 	 * Wraps around iterator and caches its keys and values during iteration.
 	 * This allows the data to be re-iterated multiple times.

tests/Utils/Arrays.mapWithKeys().phpt

@@ -0,0 +1,65 @@
+<?php
+
+/**
+ * Test: Nette\Utils\Arrays::mapWithKeys()
+ */
+
+declare(strict_types=1);
+
+use Nette\Utils\Arrays;
+use Tester\Assert;
+
+
+require __DIR__ . '/../bootstrap.php';
+
+
+test('empty array', function () {
+	$arr = [];
+	$log = [];
+	$res = Arrays::mapWithKeys(
+		$arr,
+		function ($v, $k, $arr) use (&$log) {
+			$log[] = func_get_args();
+			return [];
+		},
+	);
+	Assert::same([], $res);
+	Assert::same([], $log);
+});
+
+test('list', function () {
+	$arr = ['a', 'b'];
+	$log = [];
+	$res = Arrays::mapWithKeys(
+		$arr,
+		function ($v, $k, $arr) use (&$log) {
+			$log[] = func_get_args();
+			return ["_$k", "_$v"];
+		},
+	);
+	Assert::same(['_0' => '_a', '_1' => '_b'], $res);
+	Assert::same([['a', 0, $arr], ['b', 1, $arr]], $log);
+});
+
+test('array with keys', function () {
+	$arr = ['x' => 'a', 'y' => 'b'];
+	$log = [];
+	$res = Arrays::mapWithKeys(
+		$arr,
+		function ($v, $k, $arr) use (&$log) {
+			$log[] = func_get_args();
+			return ["_$k", "_$v"];
+		},
+	);
+	Assert::same(['_x' => '_a', '_y' => '_b'], $res);
+	Assert::same([['a', 'x', $arr], ['b', 'y', $arr]], $log);
+});
+
+test('skipped elements', function () {
+	$arr = ['x' => 'a', 'y' => 'b', 'z' => 'c'];
+	$res = Arrays::mapWithKeys(
+		$arr,
+		fn($v, $k) => $k === 'y' ? null : ["_$k", "_$v"],
+	);
+	Assert::same(['_x' => '_a', '_z' => '_c'], $res);
+});

tests/Utils/Iterables.mapWithKeys().phpt

@@ -0,0 +1,50 @@
+<?php
+
+/**
+ * Test: Nette\Utils\Iterables::mapWithKeys()
+ */
+
+declare(strict_types=1);
+
+use Nette\Utils\Iterables;
+use Tester\Assert;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+test('empty iterable', function () {
+	$arr = new ArrayIterator([]);
+	$log = [];
+	$res = Iterables::mapWithKeys(
+		$arr,
+		function ($v, $k, $arr) use (&$log) {
+			$log[] = func_get_args();
+			return [];
+		},
+	);
+	Assert::same([], iterator_to_array($res));
+	Assert::same([], $log);
+});
+
+test('non-empty iterable', function () {
+	$arr = new ArrayIterator(['x' => 'a', 'y' => 'b']);
+	$log = [];
+	$res = Iterables::mapWithKeys(
+		$arr,
+		function ($v, $k, $arr) use (&$log) {
+			$log[] = func_get_args();
+			return ["_$k", "_$v"];
+		},
+	);
+	Assert::same(['_x' => '_a', '_y' => '_b'], iterator_to_array($res));
+	Assert::same([['a', 'x', $arr], ['b', 'y', $arr]], $log);
+});
+
+test('skipped elements', function () {
+	$arr = new ArrayIterator(['x' => 'a', 'y' => 'b', 'z' => 'c']);
+	$res = Iterables::mapWithKeys(
+		$arr,
+		fn($v, $k) => $k === 'y' ? null : ["_$k", "_$v"],
+	);
+	Assert::same(['_x' => '_a', '_z' => '_c'], iterator_to_array($res));
+});