修复低版本php不兼容aray_column的问题

@@ -108,11 +108,51 @@ class ClassModel
         foreach ($classesData as $val) {
         foreach ($classesData as $val) {
             foreach ($val['ca'] as $single) {
             foreach ($val['ca'] as $single) {
                 $classes[$single['id']] = $single['name'];
                 $classes[$single['id']] = $single['name'];
-                $classes += array_column($single['sub'], 'name', 'id');
+                $classes += self::array_column($single['sub'], 'name', 'id');
             }
             }
         }
         }
 
 
         return $classes;
         return $classes;
     }
     }
+
+
+    /**
+     * 自定义array_column函数
+     * 
+     * @return array  返回数组中指定的一列组成的数组
+     */
+    /**
+     * 自定义array_column函数
+     * @param  array  $input     需要取出数组咧的多维数组
+     * @param  string $columnKey 需要返回的列
+     * @param  mixed $indexKey  作为返回数组的索引值
+     * @return array            从多维数组中返回单列数组 
+     */
+    private static function array_column(array $input, $columnKey, $indexKey = null)
+    {
+        $array = array();
+        foreach ($input as $value) {
+            if ( ! isset($value[$columnKey])) {
+                trigger_error("Key \"$columnKey\" does not exist in array");
+                return false;
+            }
+            if (is_null($indexKey)) {
+                $array[] = $value[$columnKey];
+            }
+            else {
+                if ( ! isset($value[$indexKey])) {
+                    trigger_error("Key \"$indexKey\" does not exist in array");
+                    return false;
+                }
+                if ( ! is_scalar($value[$indexKey])) {
+                    trigger_error("Key \"$indexKey\" does not contain scalar value");
+                    return false;
+                }
+                $array[$value[$indexKey]] = $value[$columnKey];
+            }
+        }
+        return $array;
+            
+    }
     
     
 }
 }