Trait SliceExt

Source

pub trait SliceExt<T> {
    // Required methods
    fn combinations<const K: usize>(&self) -> SliceCombinations<'_, T, K> ⓘ;
    fn permutations<const K: usize>(&self) -> SlicePermutations<'_, T, K> ⓘ;
}

Expand description

An extension trait adding combinations and permutations to Slice.

Required Methods§

Source

fn combinations<const K: usize>(&self) -> SliceCombinations<'_, T, K> ⓘ

Return an iterator that iterates over the k-length combinations of the elements from a slice.

The iterator produces a new array per iteration, and returns references to the elements of the slice. If K is greater than the length of the input slice the resulting iterator will yield no items.

§Examples

use const_combinations::SliceExt;

let mut combinations = [1, 2, 3, 4].combinations();
assert_eq!(combinations.next(), Some([&1, &2, &3]));
assert_eq!(combinations.next(), Some([&1, &2, &4]));
assert_eq!(combinations.next(), Some([&1, &3, &4]));
assert_eq!(combinations.next(), Some([&2, &3, &4]));
assert_eq!(combinations.next(), None);

Note: Combinations does not take into account the equality of the slice elements.

let mut combinations = [1, 2, 2].combinations();
assert_eq!(combinations.next(), Some([&1, &2])); // Note: these are the same
assert_eq!(combinations.next(), Some([&1, &2])); // Note: these are the same
assert_eq!(combinations.next(), Some([&2, &2]));
assert_eq!(combinations.next(), None);

Source

fn permutations<const K: usize>(&self) -> SlicePermutations<'_, T, K> ⓘ

Return an iterator that iterates over the k-length permutations of the elements from a slice.

The iterator produces a new array per iteration, and clones the iterator elements. If K is greater than the length of the input slice the resulting iterator adaptor will yield no items.

§Examples

let mut permutations = [0, 1, 2].permutations();
assert_eq!(permutations.next(), Some([&0, &1]));
assert_eq!(permutations.next(), Some([&1, &0]));
assert_eq!(permutations.next(), Some([&0, &2]));
assert_eq!(permutations.next(), Some([&2, &0]));
assert_eq!(permutations.next(), Some([&1, &2]));
assert_eq!(permutations.next(), Some([&2, &1]));
assert_eq!(permutations.next(), None);

Note: Permutations does not take into account the equality of the slice elements.

let mut permutations = [2, 2].permutations();
assert_eq!(permutations.next(), Some([&2, &2])); // Note: these are the same
assert_eq!(permutations.next(), Some([&2, &2])); // Note: these are the same
assert_eq!(permutations.next(), None);