Object c有没有类似java的indexOf方法获取字符串某个字符所在位置

Question

比如：

NSString *str=@"asdf.txt";

要判断是否包含  . 包含则截取后缀

Answer 1

NSString *str = @"asdf.txt";
NSRange destRange = [str rangeOfString:@"." options:NSBackwardsSearch];
if (destRange.location != NSNotFound) {
    NSString *result = [str substringFromIndex:destRange.location];
    NSLog(@"%@",result);
}