gleam/pair

first

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

Returns the first element in a pair.

first(#(1, 2))
// -> 1

</>

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

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

#(1, 2) |> map_first(fn(n) { n * 2 })
// -> #(2, 2)

</>

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

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

#(1, 2) |> map_second(fn(n) { n * 2 })
// -> #(1, 4)

</>

pub fn new(first: a, second: b) -> #(a, b)

Returns a new pair with the given elements. This can also be done using the dedicated syntax instead: new(1, 2) == #(1, 2).

## Examples

new(1, 2)
// -> #(1, 2)

</>

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

Returns the second element in a pair.

second(#(1, 2))
// -> 2

</>

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

Returns a new pair with the elements swapped.

swap(#(1, 2))
// -> #(2, 1)