文字列に指定の文字列が含まれているか判定
BOOL has = [self hasSpecifiedString:@"abcdefg" searchString:@"cde"];
-(BOOL)hasSpecifiedString:(NSString*)targetString searchString:(NSString*)searchString
{
    NSRange searchResult = [targetString rangeOfString:searchString];
    return !(searchResult.location==NSNotFound);
}