Tuples

Tuples

Tuples are fixed-size collections that can hold values of different types:

let pair = #(1, "hello")
let triple = #(True, 42, "world")

Unlike lists, tuples can contain mixed types and have a fixed size known at compile time.

Accessing Tuple Elements

Use pattern matching to access tuple elements:

let point = #(3, 4)
let #(x, y) = point
// x = 3, y = 4

You can also access elements by index with .0, .1, etc.:

let point = #(3, 4)
point.0  // 3
point.1  // 4

Multiple Return Values

Tuples are commonly used to return multiple values from a function:

fn min_max(numbers: List(Int)) -> #(Int, Int) {
  // Return both minimum and maximum
  #(minimum, maximum)
}

let #(min, max) = min_max([3, 1, 4, 1, 5])

Pattern Matching with Tuples

You can pattern match on tuples in case expressions:

case #(status, value) {
  #("ok", v) -> "Success: " <> v
  #("error", msg) -> "Error: " <> msg
  #(_, _) -> "Unknown"
}

The Pair Module

The gleam/pair module provides utilities for 2-element tuples:

import gleam/pair

pair.first(#(1, "a"))      // 1
pair.second(#(1, "a"))     // "a"
pair.swap(#(1, "a"))       // #("a", 1)
pair.map_first(#(1, "a"), fn(x) { x + 1 })  // #(2, "a")

Your Task

Write a function called swap that takes a tuple of two strings and returns them swapped. Write another function called format_pair that takes a #(String, String) tuple and returns it as "(first, second)".

Print the formatted original and swapped pairs.