Match
When you have many choices, using match is easier than writing lots of if...else .
match is used to select one of many code blocks to be executed:
Example
fn main() {
let day = 4;
match day {
1 => println!("Monday"), 2 => println!("Tuesday"), 3 => println!("Wednesday"), 4 => println!("Thursday"), 5 => println!("Friday"), 6 => println!("Saturday"), 7 => println!("Sunday"), _ => println!("Invalid day."), }
}Example explained
- The match variable ( day ) is evaluated once.
- The value of the day variable is compared with the values of each "branch"
- Each branch starts with a value, followed by => and a result
- If there is a match, the associated block of code is executed
- _ is used to specify some code to run if there is no match (like default in other languages).
- In the example above, the value of day is 4 , meaning "Thursday" will be printed
Multiple Matches
You can match multiple values at once using the | operator (OR):
Example
fn main() {
let day = 6;
match day {
1 | 2 | 3 | 4 | 5 => println!("Weekday"), 6 | 7 => println!("Weekend"), _ => println!("Invalid day"), }
}match with a Return Value
Just like if , match can also return a value:
This means you can save the result of a match into a variable:
Example
fn main() {
let day = 4;
let result = match day {
1 => "Monday", 2 => "Tuesday", 3 => "Wednesday", 4 => "Thursday", 5 => "Friday", 6 => "Saturday", 7 => "Sunday", _ => "Invalid day.", };
println!("{}", result);
}Note
Each part of the match branches must be the same type - just like with if...else .