Docs / API / Stdlib / Pair

Pair

This module provides functions to work with pairs, which are 2-element tuples.

t

RESCRIPT

type t<'a, 'b> = ('a, 'b)

first

RESCRIPT

let first: (('a, 'b)) => 'a

first(pair) returns the first element of a pair.

Examples

RESCRIPT
Pair.first((1, 2)) == 1

second

RESCRIPT

let second: (('a, 'b)) => 'b

second(pair) returns the second element of a pair.

Examples

RESCRIPT
Pair.second((1, 2)) == 2

ignore

RESCRIPT

let ignore: ('a, 'b) => unit

ignore(pair) ignores the provided pair and returns unit.

This helper is useful when you want to discard a value (for example, the result of an operation with side effects) without having to store or process it further.

equal

RESCRIPT

let equal: (
  ('a, 'b),
  ('c, 'd),
  ('a, 'c) => bool,
  ('b, 'd) => bool,
) => bool

equal(pair1, pair2, f1, f2) check equality of pair2 and pair2 using f1 for equality on the first element and f2 for equality on the second element.

Examples

RESCRIPT
Pair.equal((1, "test"), (1, "test"), Int.equal, String.equal) == true

Pair.equal((1, "test"), (2, "test"), Int.equal, String.equal) == false

compare

RESCRIPT

let compare: (
  ('a, 'b),
  ('c, 'd),
  ('a, 'c) => float,
  ('b, 'd) => float,
) => float

compare(pair1, pair2, f1, f2) compares two pairs, using f1 to compare the first element and f2 to compare the second element. Ordering is based on the first element, if they are equal, the second element is compared.

Examples

RESCRIPT
Pair.compare((1, "a"), (1, "a"), Int.compare, String.compare) == Ordering.equal
Pair.compare((1, "a"), (1, "b"), Int.compare, String.compare) == Ordering.less
Pair.compare((2, "a"), (1, "b"), Int.compare, String.compare) == Ordering.greater