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How to use the match operator in Rust

Educative Answers Team

match is a control flow operator in Rust that is used to transfer control to a particular block of code based on the value of the variable being tested. This operator is the equivalent of the switch statement in languages like C++, JavaScript, and Java.

The match operator takes in a variable and compares its value with each case value. If there is a match, the corresponding block of code is executed.

Code

Example 1

Suppose that you want to display the season corresponding to the given input. Take a look at the code below to see how the match operator would come in handy in this situation​​.

fn main() {
    let input = 2;
    match input {
        // If the input is 0, print Summer
        0 => println!("Summer"),
        // If the input is 1, print Winter
        1 => println!("Winter"),
        // If the input is 2, print Autumn
        2 => println!("Autumn"),
        // If the input is 3, print Spring
        3 => println!("Spring"),
        // If input does not match 0, 1, 2 or 3, print
        // invalid input
        _ => println!("Invalid input")

    }
}

Example 2

In match, multiple things can be matched against a single statement:

fn main() {
    let input = 4;
    match input {
        // If the input is 0, print Summer
        0 => println!("Summer"),
        // If the input is 1, print Winter
        1 => println!("Winter"),
        // If the input is 2, print Autumn
        2 => println!("Autumn"),
        // If the input is 3 or 4, print Spring
        3 | 4 => println!("Spring"),
        // If input does not match 0, 1, 2, 3 or 4, print
        // invalid input
        _ => println!("Invalid input")

    }
}

Example 3

The following code shows how you can match against ranges:

fn main() {
    let input = 19;
    match input {
        // If the input is 0, print Summer
        0 => println!("Summer"),
        // If the input is 1, print Winter
        1 => println!("Winter"),
        // If the input is between 2 and 20 (both inclusive), print Autumn
        2...20 => println!("Autumn"),
        // If the input is 21, print Spring
        21 => println!("Spring"),
        // If input does not fall between 0 and 21 (both inclusive), print
        // invalid input
        _ => println!("Invalid input")

    }
}

Remember, match is not restricted to numeric data types. Other data types like string and boolean can also be used. For more details, refer to the official documentation.

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rust
match
conditional
operator
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