+(NSString *) stringDeleteString:(NSString *)str{    NSMutableString *str1 = [NSMutableString stringWithString:str];    for (int i = 0; i < str1.length; i++) {        unichar c = [str1 characterAtIndex:i];        NSRange range = NSMakeRange(i, 1);        if (|| c == '"' || c == '.' || c == ',' || c == '(' || c == ')') { //此处可以是任何字符            [str1 deleteCharactersInRange:range];            --i;        }    }    NSString *newstr = [NSString stringWithString:str1];    return newstr;}

可以删除nsstring中的数字、符号，或者修改其中的字符