Added Arr::isList() helper (#39277)

Author: PHLAK

src/Illuminate/Collections/Arr.php

@@ -393,6 +393,19 @@ public static function isAssoc(array $array)
         return array_keys($keys) !== $keys;
     }
 
+    /**
+     * Determines if an array is a list.
+     *
+     * An array is a "list" if all array keys are sequential integers starting from 0 with no gaps in between.
+     *
+     * @param  array  $array
+     * @return bool
+     */
+    public static function isList($array)
+    {
+        return ! self::isAssoc($array);
+    }
+
     /**
      * Get a subset of the items from the given array.
      *

tests/Support/SupportArrTest.php

@@ -424,6 +424,22 @@ public function testIsAssoc()
         $this->assertFalse(Arr::isAssoc(['a', 'b']));
     }
 
+    public function testIsList()
+    {
+        $this->assertTrue(Arr::isList([]));
+        $this->assertTrue(Arr::isList([1, 2, 3]));
+        $this->assertTrue(Arr::isList(['foo', 2, 3]));
+        $this->assertTrue(Arr::isList(['foo', 'bar']));
+        $this->assertTrue(Arr::isList([0 => 'foo', 'bar']));
+        $this->assertTrue(Arr::isList([0 => 'foo', 1 => 'bar']));
+
+        $this->assertFalse(Arr::isList([1 => 'foo', 'bar']));
+        $this->assertFalse(Arr::isList([1 => 'foo', 0 => 'bar']));
+        $this->assertFalse(Arr::isList([0 => 'foo', 'bar' => 'baz']));
+        $this->assertFalse(Arr::isList([0 => 'foo', 2 => 'bar']));
+        $this->assertFalse(Arr::isList(['foo' => 'bar', 'baz' => 'qux']));
+    }
+
     public function testOnly()
     {
         $array = ['name' => 'Desk', 'price' => 100, 'orders' => 10];