rustHow to compare with null in Rust

Comparing with null in Rust is done using the Option enum. Option is an enum with two variants, Some and None. Some is used to wrap a value, while None is used to represent the absence of a value.

Example code

let x = Some(5);
let y = None;

match x {
    Some(i) => println!("x is {}", i),
    None => println!("x is None"),
}

match y {
    Some(i) => println!("y is {}", i),
    None => println!("y is None"),
}

Output example

x is 5
y is None

Code explanation

1. let x = Some(5);: This line declares a variable x and assigns it the value Some(5). Some is a variant of the Option enum, and it wraps the value 5.
2. let y = None;: This line declares a variable y and assigns it the value None. None is a variant of the Option enum, and it represents the absence of a value.
3. match x {: This line starts a match expression, which is used to compare the value of x with the variants of the Option enum.
4. Some(i) => println!("x is {}", i),: This line is a match arm, and it is used to handle the case where x is equal to Some. The value wrapped by Some is assigned to the variable i, and then it is printed.
5. None => println!("x is None"),: This line is a match arm, and it is used to handle the case where x is equal to None. It prints a message indicating that x is None.

Helpful links

• Rust Book - Match
• Rust Book - Option

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