Trait SliceExt

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

An extension trait adding combinations and permutations to Slice.

Required Methods

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);

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);

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<T> SliceExt<T> for [T]

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

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

Implementors