The match statement in Rust is a powerful control flow construct used for pattern matching. It allows you to match a value against a series of patterns and execute different code blocks based on the matched pattern.
Example code:
fn main() {
let number = 7;
match number {
1 => println!("One"),
2 => println!("Two"),
3 => println!("Three"),
_ => println!("Other"),
}
}
Matching Against Multiple Patterns
In Rust, you can match against multiple patterns in a single match statement. The first matching pattern will be executed.
Example code:
fn main() {
let number = 3;
match number {
1 | 2 => println!("One or Two"),
3 | 4 => println!("Three or Four"),
_ => println!("Other"),
}
}
Matching with Binding
The match statement in Rust allows you to bind the matched value to a variable, which can be used in the corresponding code block.
Example code:
fn main() {
let number = Some(7);
match number {
Some(n) => println!("Found a number: {}", n),
None => println!("No number found"),
}
}
Ignoring Values
If you don't need to use the matched value, you can use the underscore (_) pattern to ignore it.
Example code:
fn main() {
let number = Some(7);
match number {
Some(_) => println!("Found a number"),
None => println!("No number found"),
}
}
Matching with Guards
Rust's match statement supports guards, which are additional conditions that can be added to the patterns.
Example code:
fn main() {
let age = 18;
match age {
0..=17 => println!("Underage"),
18..=65 => println!("Adult"),
_ => println!("Senior Citizen"),
}
}
I hope these help you understand the Rust match statement better!
Here are a few more examples of using the match statement in Rust:
Example 1: Matching Enum Variants
enum Message {
Quit,
Move { x: i32, y: i32 },
Write(String),
ChangeColor(i32, i32, i32),
}
fn process_message(msg: Message) {
match msg {
Message::Quit => println!("Quit message received"),
Message::Move { x, y } => println!("Move to {}, {}", x, y),
Message::Write(text) => println!("Write message: {}", text),
Message::ChangeColor(r, g, b) => println!("Change color to ({}, {}, {})", r, g, b),
}
}
fn main() {
let msg1 = Message::Move { x: 10, y: 20 };
let msg2 = Message::Write(String::from("Hello, Rust!"));
process_message(msg1);
process_message(msg2);
}
Example 2: Matching Option Values
fn get_favorite_fruit(name: &str) -> Option<&str> {
match name {
"Alice" => Some("Apple"),
"Bob" => Some("Banana"),
_ => None,
}
}
fn main() {
let name1 = "Alice";
let name2 = "Charlie";
match get_favorite_fruit(name1) {
Some(fruit) => println!("{}'s favorite fruit is {}", name1, fruit),
None => println!("{}'s favorite fruit is unknown", name1),
}
match get_favorite_fruit(name2) {
Some(fruit) => println!("{}'s favorite fruit is {}", name2, fruit),
None => println!("{}'s favorite fruit is unknown", name2),
}
}
Example 3: Matching Ranges
fn main() {
let score = 85;
match score {
0..=59 => println!("Failed"),
60..=79 => println!("Passed"),
80..=100 => println!("Excellent"),
_ => println!("Invalid score"),
}
}
Example 4: Matching with Guards
fn main() {
let age = 25;
let student = false;
match age {
0..=17 if !student => println!("Child"),
0..=17 if student => println!("Student"),
18..=65 => println!("Adult"),
_ => println!("Senior Citizen"),
}
}
Top comments (1)
Don't forget to share your thoughts about match in comment.