Trait join_string::Join

source ·

pub trait Join<I: Iterator> {
    // Required method
    fn iter(self) -> I;

    // Provided methods
    fn join<S>(self, sep: S) -> Joiner<I, S>
       where Self: Sized,
             S: Display,
             I::Item: Display { ... }
    fn join_str<S>(self, sep: S) -> Joiner<DisplayIter<I>, DisplayWrapper<S>>
       where Self: Sized,
             S: AsRef<str>,
             I::Item: AsRef<str> { ... }
}

Expand description

Trait that provides a method to join elements of an iterator, interspersing a separator between all elements.

It is also implemented for a few common types that aren’t iterators, but have an iter() method. Among these types are arrays, slices, and Vecs.

Required Methods§

source

fn iter(self) -> I

Provided Methods§

source

fn join<S>(self, sep: S) -> Joiner<I, S>where Self: Sized, S: Display, I::Item: Display,

Examples found in repository ?

examples/reverse_words.rs (line 5)

pub fn reverse_words(s: impl AsRef<str>) -> String {
    s.as_ref().split_whitespace()
         .map(|s| s.chars().rev().join(""))
         .join(" ")
         .into_string()
}

fn main() {
    println!("{}", reverse_words("foo bar baz"));

    println!("{}",
        "foo bar baz".split_whitespace()
            .map(|s| s.chars().rev().join(""))
            .join(" "));

    println!("{}",
        "foo bar baz".split_whitespace()
            .map(|s| s.chars().rev().map(|c| char::from_u32(c as u32 + 1u32).unwrap_or('?')).join(""))
            .join(" "));

    // inefficient temporary strings
    println!("{}",
        "foo bar baz".split_whitespace()
            .map(|s| s.chars().rev().map(|c| format!("<{c}>")).join(""))
            .join(" "));

    // inefficient temporary strings
    println!("{}", std::env::args().map(|s| s.chars().rev().collect::<String>()).join(" ").into_string());
}

More examples

Hide additional examples

examples/file.rs (line 14)

fn main() -> std::io::Result<()> {
    let mut args = std::env::args().skip(1);

    let filename = args.next().expect(USAGE);
    let sep = args.next().expect(USAGE);

    let file = File::create(filename)?;

    args.join(sep).write_io(file)?;

    Ok(())
}

examples/simple.rs (line 4)

fn main() -> std::io::Result<()> {
    println!("{}", ["foo", "bar", "baz"].iter().join(", "));
    println!("{}", ['a', 'b', 'c'].iter().join(", "));
    println!("{}", ["foo".to_owned(), "bar".to_owned(), "baz".to_owned()].iter().join(", "));
    println!("{}", vec![1, 2, 3].iter().cycle().take(5).join(", "));
    println!("{}", "äüö".chars().join(' '));
    std::env::args().join(", ").write_io(std::io::stdout())?;
    println!();

    // inefficient temporary string
    let str: String = std::env::args().join(", ").into();
    println!("{}", str);

    Ok(())
}