full_join

In std/collections.

fn full_join<T, U, K, R>(self: Seq<T>, other: Seq<U>, *, left: T -> K, right: U -> K, on: (T, U) -> Bool, into: (Option<T>, Option<U>) -> R) : Seq<R>
fn full_join<T, U, K, R>(self: Seq<T>, other: Seq<U>, *, left: T -> K, right: U -> K, into: (Option<T>, Option<U>) -> R) : Seq<R>
fn full_join<T, U, R>(self: Seq<T>, other: Seq<U>, *, on: (T, U) -> Bool, into: (Option<T>, Option<U>) -> R) : Seq<R>

A join that keeps every element of both sides, with none for the missing side; the unmatched elements of other come after the matched results.