• ImplyingImplications@lemmy.ca
    82·
    20 hours ago

    Me, every time I try searching a Rust question.

    That’s easy. Just do:

    fn is_second_num_positive() -> bool {
    let input = "123,-45";
    let is_positive =
        input.split(',')
        .collect::<Vec<&str>>()
        .last()
        .unwrap()
        .parse::<i32>()
        .unwrap()
        .is_positive();
    is_positive
}
    • shape_warrior_t@programming.devEnglish
      14·
      18 hours ago

      Can’t resist pointing out how you should actually write the function in a “real” scenario (but still not handling errors properly), in case anyone wants to know.

      If the list is guaranteed to have exactly two elements:

      fn is_second_num_positive_exact(input: &str) -> bool {
    let (_, n) = input.split_once(',').unwrap();
    n.parse::<i32>().unwrap() > 0
}

      If you want to test the last element:

      fn is_last_num_positive(input: &str) -> bool {
    let n = input.split(',').next_back().unwrap();
    n.parse::<i32>().unwrap() > 0
}

      If you want to test the 2nd (1-indexed) element:

      fn is_second_num_positive(input: &str) -> bool {
    let n = input.split(',').nth(1).unwrap();
    n.parse::<i32>().unwrap() > 0
}
      • beeb@lemmy.zip
        2·
        8 hours ago

        Even better to use expect with a short message of what the assumption is: “the string should contain a comma” if it ever panics you’ll know exactly why.