rustHow to check a value for null in Rust

To check a value for null in Rust, you can use the Option type. Option is an enum with two variants: Some and None. Some is used to wrap a value, while None is used to indicate the absence of a value.

Example code

let x: Option<i32> = Some(5);

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

Output example

x is 5

Code explanation

• let x: Option<i32> = Some(5);: This line declares a variable x of type Option<i32> and assigns it the value Some(5).
• match x {: This line starts a match expression, which is used to compare a value against a list of patterns and execute code based on which pattern matches.
• Some(i) => println!("x is {}", i): This line is a pattern that matches the Some variant of the Option type. If this pattern matches, the code println!("x is {}", i) is executed, where i is the value wrapped in the Some variant.
• None => println!("x is None"): This line is a pattern that matches the None variant of the Option type. If this pattern matches, the code println!("x is None") is executed.

Helpful links

• Rust Book - Match
• Rust Book - Option

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