删除字符串中某字符

if ([num intValue] == 0) {
        num = @1;
       
        if ([self.mString containsString:sort.adTypeName]) {
           
        } else {
            [self.mString appendFormat:@"%@,", sort.adTypeName];
        }
       
    } else {
        num = @0;
        //获取到该字符串的位置.根据位置将字符串删除
        NSRange range = [self.mString rangeOfString:sort.adTypeName];
       
        [self.mString deleteCharactersInRange:NSMakeRange(range.location, range.length + 1)];

}