修改

application/inter/controller/Doctors.php

@@ -109,7 +109,7 @@ class Doctors extends Base
         {
             return 0;
         }
-        $preg = "/^[0-9_a-zA-Z]{6,20}$/";
+        $preg = "/^(?![0-9]+$)(?![a-zA-Z]+$)[0-9A-Za-z_]{6,20}$/";
         return preg_match($preg,$str);
     }