NSCharacterSet

iOS中NSCharacterSet的使用详解 - CSDN博客 

在不同的字符上做过滤、

if( [strPath rangeOfCharacterFromSet:[NSCharacterSet characterSetWithCharactersInString:@"/\\"]].location!=NSNotFound )

/例子1:去除两边的空格  

 string =  [stringstringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]；  

//过滤一些字符

 NSString *string = @"123a bc 9ABC";

 NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:NUM] invertedSet];         NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];