         self.string = string
     }
 
-    
+
     // MARK: - Basic
     /// 字符串长度
     public var length: Int {

        let end = index(startIndex, offsetBy: subrange.upperBound)
        removeSubrange(start ..< end)
    }
}



                return ""
        }
        return String(self[startIndex ..< endIndex])
    }

    /// 在字符串指定位置插入一个字符
