Rust by Example

   • Destructuring Tuples

   • Destructuring Enums

   • Destructuring Pointers

   • Destructuring Structures

tuples

Tuples can be destructured in a match as follows:

fn main() {

let triple = (0, -2, 3);

// TODO ^ Try different values for `triple`

println!("Tell me about {:?}", triple);

// Match can be used to destructure a tuple

match triple {

// Destructure the second and third elements

(0, y, z) => println!("First is `0`, `y` is {:?}, and `z` is {:?}", y, z),

(1, ..) => println!("First is `1` and the rest doesn't matter"),

// `..` can be the used ignore the rest of the tuple

_ => println!("It doesn't matter what they are"),

// `_` means don't bind the value to a variable

}

}

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See also:

Tuples

enums

An enum is destructured similarly:

// `allow` required to silence warnings because only

// one variant is used.

#[allow(dead_code)]

enum Color {

// These 3 are specified solely by their name.

Red,

Blue,

Green,

// These likewise tie `u32` tuples to different names: color models.

RGB(u32, u32, u32),

HSV(u32, u32, u32),

HSL(u32, u32, u32),

CMY(u32, u32, u32),

CMYK(u32, u32, u32, u32),

}

fn main() {

let color = Color::RGB(122, 17, 40);

// TODO ^ Try different variants for `color`

println!("What color is it?");

// An `enum` can be destructured using a `match`.

match color {

Color::Red => println!("The color is Red!"),

Color::Blue => println!("The color is Blue!"),

Color::Green => println!("The color is Green!"),

Color::RGB(r, g, b) =>

println!("Red: {}, green: {}, and blue: {}!", r, g, b),

Color::HSV(h, s, v) =>

println!("Hue: {}, saturation: {}, value: {}!", h, s, v),

Color::HSL(h, s, l) =>

println!("Hue: {}, saturation: {}, lightness: {}!", h, s, l),

Color::CMY(c, m, y) =>

println!("Cyan: {}, magenta: {}, yellow: {}!", c, m, y),

Color::CMYK(c, m, y, k) =>

println!("Cyan: {}, magenta: {}, yellow: {}, key (black): {}!",

c, m, y, k),

// Don't need another arm because all variants have been examined

}

}