diff --git a/docs/guide/helper-array.md b/docs/guide/helper-array.md
index 410fe5c198..698b8e795b 100644
--- a/docs/guide/helper-array.md
+++ b/docs/guide/helper-array.md
@@ -312,7 +312,8 @@ or an anonymous function like the following one:
 
 ```php
 ArrayHelper::multisort($data, function($item) {
-    return isset($item['age']) ? ['age', 'name'] : 'name';
+    // sort by age if it exists or by name otherwise
+    return isset($item['age']) ? $item['age'] : $item['name'];
 });
 ```
 
diff --git a/framework/helpers/BaseArrayHelper.php b/framework/helpers/BaseArrayHelper.php
index 9ad77c8e93..c5deb6f3de 100644
--- a/framework/helpers/BaseArrayHelper.php
+++ b/framework/helpers/BaseArrayHelper.php
@@ -648,9 +648,9 @@ class BaseArrayHelper
             throw new InvalidArgumentException('The length of $sortFlag parameter must be the same as that of $keys.');
         }
         $args = [];
-        foreach ($keys as $i => $key) {
+        foreach ($keys as $i => $k) {
             $flag = $sortFlag[$i];
-            $args[] = static::getColumn($array, $key);
+            $args[] = static::getColumn($array, $k);
             $args[] = $direction[$i];
             $args[] = $flag;
         }