字符串常用操作

1.将字符串 @"13385739275"中,从 8提取到3。替换 成@"**** "。及常用的手机号中间四位设为*号

        
       //方法一
     NSMutableString* mutableString = [NSMutableString stringWithFormat:@"13385739275"];
     [mutableString replaceCharactersInRange:NSMakeRange(3, 4) withString:@"****"];
     NSLog(@"mutableString:%@",mutableString);
    
    
    //方法二  先删除 再插入
   
     [mutableString deleteCharactersInRange:NSMakeRange(3,4)];
     //NSLog(@"%@", mutableString);
     [mutableString insertString:@"****" atIndex:3];
     NSLog(@"mutableString2:%@", mutableString);
  
    
    //方法三
    
    NSString * mutableString3 = [mutableString stringByReplacingOccurrencesOfString:@"8573" withString:@"****"];
    NSLog(@"mutableString3:%@", mutableString3);