feat: get duplicate by column helpers

system/Helpers/Array/ArrayHelper.php

@@ -319,4 +319,44 @@ public static function sortValuesByNatural(array &$array, $sortByIndex = null):
             return strnatcmp((string) $currentValue, (string) $nextValue);
         });
     }
+
+    /**
+     * Duplicate Array Check by Column
+     *
+     * @param array|string $column Unique Column
+     * @param array        $data   Array Data
+     */
+    public static function arrayDuplicatesBy($column, array $data = []): array
+    {
+        if ($data === []) {
+            return [];
+        }
+
+        $duplicateData = [];
+        $dataUnique    = [];
+
+        foreach ($data as $lineIndex => $searchData) {
+            if (is_array($column)) {
+                foreach ($column as $rawColumn) {
+                    if (in_array($searchData[$rawColumn], $dataUnique[$rawColumn] ?? [], true)) {
+                        $duplicateData[$lineIndex][$rawColumn] = $searchData[$rawColumn];
+                    } else {
+                        $dataUnique[$rawColumn][] = $searchData[$rawColumn];
+                    }
+                }
+            }
+
+            if (is_string($column)) {
+                if (in_array($searchData[$column], $dataUnique[$column] ?? [], true)) {
+                    $duplicateData[$lineIndex][$column] = $searchData[$column];
+                } else {
+                    $dataUnique[$column][] = $searchData[$column];
+                }
+            }
+        }
+
+        unset($dataUnique);
+
+        return $duplicateData;
+    }
 }

system/Helpers/array_helper.php

@@ -15,6 +15,21 @@
 
 // CodeIgniter Array Helpers
 
+if (! function_exists('array_duplicate_by')) {
+    /**
+     * Duplicate array check by column.
+     *
+     * @param array|string $column Unique Column
+     * @param array        $data   Array Data
+     *
+     * @return array
+     */
+    function array_duplicate_by($column, array $data = [])
+    {
+        return ArrayHelper::arrayDuplicatesBy($column, $data);
+    }
+}
+
 if (! function_exists('dot_array_search')) {
     /**
      * Searches an array through dot syntax. Supports

tests/system/Helpers/Array/ArrayHelperDuplicateCheckTest.php

@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <[email protected]>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Helpers\Array;
+
+use CodeIgniter\Test\CIUnitTestCase;
+
+/**
+ * @group Others
+ *
+ * @internal
+ */
+final class ArrayHelperDuplicateCheckTest extends CIUnitTestCase
+{
+    private array $array = [
+        [
+            'name' => 'Fred Flinstone',
+            'age'  => 20,
+        ],
+        [
+            'name' => 'Brad Pierce',
+            'age'  => 30,
+        ],
+        [
+            'name' => 'Fred Flinstone',
+            'age'  => 70,
+        ],
+        [
+            'name' => 'Michelle Stone',
+            'age'  => 30,
+        ],
+        [
+            'name' => 'Michael Bram',
+            'age'  => 40,
+        ],
+    ];
+
+    public function testSingleColumn(): void
+    {
+        $this->assertSame([
+            2 => [
+                'name' => 'Fred Flinstone',
+            ],
+        ], ArrayHelper::arrayDuplicatesBy('name', $this->array));
+    }
+
+    public function testMultipleColumn(): void
+    {
+        $this->assertSame([
+            2 => [
+                'name' => 'Fred Flinstone',
+            ],
+            3 => [
+                'age' => 30,
+            ],
+        ], ArrayHelper::arrayDuplicatesBy(['name', 'age'], $this->array));
+    }
+}

tests/system/Helpers/ArrayHelperTest.php

@@ -1287,4 +1287,79 @@ public static function provideArrayGroupByExcludeEmpty(): iterable
             ],
         ];
     }
+
+    /**
+     * @dataProvider provideArrayDuplicate
+     *
+     * @param mixed $column
+     */
+    public function testArrayDuplicate($column, array $data, array $expected): void
+    {
+        $this->assertSame($expected, array_duplicate_by($column, $data));
+    }
+
+    public static function provideArrayDuplicate(): iterable
+    {
+        yield 'single and multiple' => [
+            'name', // Single
+            [
+                [
+                    'name' => 'Fred Flinstone',
+                    'age'  => 20,
+                ],
+                [
+                    'name' => 'Brad Pierce',
+                    'age'  => 30,
+                ],
+                [
+                    'name' => 'Fred Flinstone',
+                    'age'  => 70,
+                ],
+                [
+                    'name' => 'Michelle Stone',
+                    'age'  => 30,
+                ],
+                [
+                    'name' => 'Michael Bram',
+                    'age'  => 40,
+                ],
+            ],
+            [
+                2 => [
+                    'name' => 'Fred Flinstone',
+                ],
+            ],
+            ['name', 'age'], // Multiple
+            [
+                [
+                    'name' => 'Fred Flinstone',
+                    'age'  => 20,
+                ],
+                [
+                    'name' => 'Brad Pierce',
+                    'age'  => 30,
+                ],
+                [
+                    'name' => 'Fred Flinstone',
+                    'age'  => 70,
+                ],
+                [
+                    'name' => 'Michelle Stone',
+                    'age'  => 30,
+                ],
+                [
+                    'name' => 'Michael Bram',
+                    'age'  => 40,
+                ],
+            ],
+            [
+                2 => [
+                    'name' => 'Fred Flinstone',
+                ],
+                3 => [
+                    'age' => 30,
+                ],
+            ],
+        ];
+    }
 }