Function core::iter::sources::repeat_n::repeat_n

pub fn repeat_n<T: Clone>(element: T, count: usize) -> RepeatN<T>

🔬This is a nightly-only experimental API. (iter_repeat_n #104434)

Creates a new iterator that repeats a single element a given number of times.

The repeat_n() function repeats a single value exactly n times.

This is very similar to using repeat() with Iterator::take(), but there are two differences:

• repeat_n() can return the original value, rather than always cloning.
• repeat_n() produces an ExactSizeIterator.

Examples

Basic usage:

#![feature(iter_repeat_n)]
use std::iter;

// four of the number four:
let mut four_fours = iter::repeat_n(4, 4);

assert_eq!(Some(4), four_fours.next());
assert_eq!(Some(4), four_fours.next());
assert_eq!(Some(4), four_fours.next());
assert_eq!(Some(4), four_fours.next());

// no more fours
assert_eq!(None, four_fours.next());

For non-Copy types,

#![feature(iter_repeat_n)]
use std::iter;

let v: Vec<i32> = Vec::with_capacity(123);
let mut it = iter::repeat_n(v, 5);

for i in 0..4 {
    // It starts by cloning things
    let cloned = it.next().unwrap();
    assert_eq!(cloned.len(), 0);
    assert_eq!(cloned.capacity(), 0);
}

// ... but the last item is the original one
let last = it.next().unwrap();
assert_eq!(last.len(), 0);
assert_eq!(last.capacity(), 123);

// ... and now we're done
assert_eq!(None, it.next());