join_string

Trait Join

Source 
pub trait Join<I: Iterator>: IntoIterator<IntoIter = I> {
    // Provided methods
    fn join<S>(self, sep: S) -> Joiner<I, S>
       where Self: Sized,
             S: 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.

This trait is implemented for anything that implements std::iter::IntoIterator, which is e.g. arrays, slices, Vec, and more.

Provided Methods§

Source

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

Join the elements of an iterator, interspersing a separator between all elements.

The elements and the separator need to implement std::fmt::Display.

Examples found in repository?
examples/reverse_words.rs (line 6)
3pub fn reverse_words(s: impl AsRef<str>) -> String {
4    s.as_ref()
5        .split_whitespace()
6        .map(|s| s.chars().rev().join(""))
7        .join(" ")
8        .into_string()
9}
10
11fn main() {
12    println!("{}", reverse_words("foo bar baz"));
13
14    println!(
15        "{}",
16        "foo bar baz"
17            .split_whitespace()
18            .map(|s| s.chars().rev().join(""))
19            .join(" ")
20    );
21
22    println!(
23        "{}",
24        "foo bar baz"
25            .split_whitespace()
26            .map(|s| s
27                .chars()
28                .rev()
29                .map(|c| char::from_u32(c as u32 + 1).unwrap_or('?'))
30                .join(""))
31            .join(" ")
32    );
33
34    // inefficient temporary strings
35    println!(
36        "{}",
37        "foo bar baz"
38            .split_whitespace()
39            .map(|s| s.chars().rev().map(|c| format!("<{c}>")).join(""))
40            .join(" ")
41    );
42
43    // inefficient temporary strings
44    println!(
45        "{}",
46        std::env::args()
47            .map(|s| s.chars().rev().collect::<String>())
48            .join(" ")
49            .into_string()
50    );
51}
More examples
Hide additional examples
examples/debug.rs (line 10)
9fn main() {
10    println!("{:?}", ['a', 'b', 'c'].join(", "));
11    println!("{:?}", [
12        &MyStruct { value: 1 },
13        &MyStruct { value: 2 },
14        &MyStruct { value: 3 },
15    ].join(", "));
16}
examples/file.rs (line 14)
6fn main() -> std::io::Result<()> {
7    let mut args = std::env::args().skip(1);
8
9    let filename = args.next().expect(USAGE);
10    let sep = args.next().expect(USAGE);
11
12    let file = File::create(filename)?;
13
14    args.join(sep).write_io(file)?;
15
16    Ok(())
17}
examples/simple.rs (line 4)
3fn main() -> std::io::Result<()> {
4    println!("{}", ["foo", "bar", "baz"].join(", "));
5    println!("{}", ['a', 'b', 'c'].join(", "));
6    println!(
7        "{}",
8        ["foo".to_owned(), "bar".to_owned(), "baz".to_owned()].join(", ")
9    );
10    println!("{}", vec![1, 2, 3].iter().cycle().take(5).join(", "));
11    println!("{}", "äüö".chars().join(' '));
12    std::env::args().join(", ").write_io(std::io::stdout())?;
13    println!();
14
15    // inefficient temporary string
16    let str: String = std::env::args().join(", ").into();
17    println!("{}", str);
18
19    Ok(())
20}
Source

fn join_str<S>(self, sep: S) -> Joiner<DisplayIter<I>, DisplayWrapper<S>>
where Self: Sized, S: AsRef<str>, I::Item: AsRef<str>,

Join the elements of an iterator, interspersing a separator between all elements.

The elements and the separator need to implement AsRef<str>.

Implementors§

Source§

impl<T> Join<<T as IntoIterator>::IntoIter> for T
where T: IntoIterator,