gleam/pair

first

pub fn first(pair: tuple(a, b)) -> a

Returns the first element in a pair.

> first(tuple(1, 2))
1

pub fn map_first(
  of pair: tuple(a, b),
  with fun: fn(a) -> c,
) -> tuple(a, b)

Returns a new pair with the first element having had with applied to it.

> tuple(1, 2) |> map_first(fn(n) { n * 2 })
2

pub fn map_second(
  of pair: tuple(a, b),
  with fun: fn(b) -> c,
) -> tuple(a, b)

Returns a new pair with the second element having had with applied to it.

> tuple(1, 2) |> map_second(fn(n) { n * 2 })
4

pub fn second(pair: tuple(a, b)) -> a

Returns the second element in a pair.

> second(tuple(1, 2))
2

pub fn swap(pair: tuple(a, b)) -> tuple(a, b)

Returns a new pair with the elements swapped.

> swap(tuple(1, 2))
tuple(2, 1)