Add Unzip operation.

docs/pages/api.rst

@@ -1527,6 +1527,23 @@ Signature: ``Collection::unwrap();``
      $collection = Collection::with($data)
         ->unwrap();
 
+unzip
+~~~~~
+
+Unzip a collection.
+
+Interface: `Unzipable`_
+
+Signature: ``Collection::unzip();``
+
+.. code-block:: php
+
+    $a = Collection::with(['a' => 'a', 'b' => 'b', 'c' => 'c'])
+        ->zip(['d', 'e', 'f', 'g'], [1, 2, 3, 4, 5]);
+
+    $b = Collection::with($a)
+        ->unzip(); // [ ['a','b','c',null,null], ['d','e','f','g',null], [1,2,3,4,5] ]
+
 window
 ~~~~~~
 
@@ -1653,6 +1670,7 @@ Signature: ``Collection::zip(iterable ...$iterables);``
 .. _Unpairable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Unpairable.php
 .. _Untilable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Untilable.php
 .. _Unwrapable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Unwrapable.php
+.. _Unzipable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Unzipable.php
 .. _Windowable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Windowable.php
 .. _Wrapable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Wrapable.php
 .. _Zipable: https://github.com/loophp/collection/blob/master/src/Contract/Operation/Zipable.php

spec/loophp/collection/CollectionSpec.php

@@ -2016,6 +2016,24 @@ public function it_can_unwrap()
             ]);
     }
 
+    public function it_can_unzip(): void
+    {
+        $this::fromIterable(range('A', 'C'))
+            ->zip(['D', 'E', 'F', 'G'], [1, 2, 3, 4, 5])
+            ->unzip()
+            ->shouldIterateAs([
+                [
+                    'A', 'B', 'C', null, null,
+                ],
+                [
+                    'D', 'E', 'F', 'G', null,
+                ],
+                [
+                    1, 2, 3, 4, 5,
+                ],
+            ]);
+    }
+
     public function it_can_use_range(): void
     {
         $this::range(0, 5)
@@ -2291,20 +2309,17 @@ public function it_can_zip(): void
     {
         $this::fromIterable(range('A', 'C'))
             ->zip(['D', 'E', 'F'])
-            ->all()
-            ->shouldReturn([['A', 'D'], ['B', 'E'], ['C', 'F']]);
+            ->shouldIterateAs([['A', 'D'], ['B', 'E'], ['C', 'F']]);
 
         $this::fromIterable(['A', 'C', 'E'])
             ->zip(['B', 'D', 'F', 'H'])
-            ->all()
-            ->shouldReturn([['A', 'B'], ['C', 'D'], ['E', 'F'], [null, 'H']]);
+            ->shouldIterateAs([['A', 'B'], ['C', 'D'], ['E', 'F'], [null, 'H']]);
 
         $collection = Collection::fromIterable(range(1, 5));
 
         $this::fromIterable($collection)
             ->zip(range('A', 'E'))
-            ->all()
-            ->shouldReturn([[1, 'A'], [2, 'B'], [3, 'C'], [4, 'D'], [5, 'E']]);
+            ->shouldIterateAs([[1, 'A'], [2, 'B'], [3, 'C'], [4, 'D'], [5, 'E']]);
     }
 
     public function it_is_initializable(): void

src/Collection.php

@@ -92,6 +92,7 @@
 use loophp\collection\Operation\Unpair;
 use loophp\collection\Operation\Until;
 use loophp\collection\Operation\Unwrap;
+use loophp\collection\Operation\Unzip;
 use loophp\collection\Operation\Window;
 use loophp\collection\Operation\Wrap;
 use loophp\collection\Operation\Zip;
@@ -731,6 +732,11 @@ public function unwrap(): CollectionInterface
         return $this->run(Unwrap::of());
     }
 
+    public function unzip(): CollectionInterface
+    {
+        return $this->run(Unzip::of());
+    }
+
     public function window(int ...$length): CollectionInterface
     {
         return $this->run(Window::of()(...$length));

src/Contract/Collection.php

@@ -85,6 +85,7 @@
 use loophp\collection\Contract\Operation\Unpairable;
 use loophp\collection\Contract\Operation\Untilable;
 use loophp\collection\Contract\Operation\Unwrapable;
+use loophp\collection\Contract\Operation\Unzipable;
 use loophp\collection\Contract\Operation\Windowable;
 use loophp\collection\Contract\Operation\Wrapable;
 use loophp\collection\Contract\Operation\Zipable;
@@ -166,6 +167,7 @@
  * @template-extends Unpairable<TKey, T>
  * @template-extends Untilable<TKey, T>
  * @template-extends Unwrapable<TKey, T>
+ * @template-extends Unzipable<TKey, T>
  * @template-extends Windowable<TKey, T>
  * @template-extends Wrapable<TKey, T>
  * @template-extends Zipable<TKey, T>
@@ -253,6 +255,7 @@ interface Collection extends
     Unpairable,
     Untilable,
     Unwrapable,
+    Unzipable,
     Windowable,
     Wrapable,
     Zipable

src/Contract/Operation/Unzipable.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace loophp\collection\Contract\Operation;
+
+use loophp\collection\Contract\Collection;
+
+/**
+ * @psalm-template TKey
+ * @psalm-template TKey of array-key
+ * @psalm-template T
+ */
+interface Unzipable
+{
+    /**
+     * @return \loophp\collection\Contract\Collection<TKey,T>
+     */
+    public function unzip(): Collection;
+}

src/Operation/Unzip.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace loophp\collection\Operation;
+
+use Closure;
+use Generator;
+use Iterator;
+
+/**
+ * @psalm-template TKey
+ * @psalm-template TKey of array-key
+ * @psalm-template T
+ */
+final class Unzip extends AbstractOperation
+{
+    /**
+     * @psalm-return Closure(Iterator<TKey, list<T>>): Generator<int, list<T>>
+     */
+    public function __invoke(): Closure
+    {
+        return
+            /**
+             * @psalm-param Iterator<TKey, list<T>> $iterator
+             *
+             * @psalm-return Generator<int, list<T>>
+             */
+            static function (Iterator $iterator): Generator {
+                $index = 0;
+                $result = [];
+
+                foreach ($iterator as $current) {
+                    foreach ($current as $c) {
+                        $result[$index++][] = $c;
+                    }
+
+                    $index = 0;
+                }
+
+                return yield from $result;
+            };
+    }
+}