Convert `bool`, `int`

Often in Rust programs we have bool variables. These can be returned from a function, or from an expression evaluation.

I32 result

By using a cast, we can directly convert a bool to an i32 value. And for non-standard conversions, a match expression can be used.

Required input, output

There are only 2 valid boolean values in programs—true and false. Logically these are usually converted to 1 and 0.

false -> 0
true  -> 1

Example code

To begin, we have an example program where we first assign some bools. And then we convert them with the simplest approach, which is an "as" cast.

Part 1 We create some example bools and use 3 different bool variables. We use an expression to set a bool.

Part 2 This is the important part, where the actual conversion from bool to int occurs.

Part 3 We test and print our results. We find that each bool is now the value 0 or 1.

fn main() {
    // Part 1: create some example bools.
    let result1 = true;
    let result2 : bool = false;

    let temp = 10;
    let result3 = temp == 10 && result1;

    // Part 2: convert bools to i32s.
    let convert1 = result1 as i32;
    let convert2 = result2 as i32;
    let convert3 = result3 as i32;

    // Part 3: test and print results.
    if convert1 == 1 {
        println!("TRUE IS 1");
    }

    println!("{} = {}", result1, convert1);
    println!("{} = {}", result2, convert2);
    println!("{} = {}", result3, convert3);
}TRUE IS 1
true = 1
false = 0
true = 1

`Match` example

It is sometimes necessary to use a more complex approach to converting bools. Here we use a logic structure, match, to branch and perform the conversion.

fn main() {
    let result1 = true;

    // Use match to convert bool with more complex logic.
    let convert1 = match result1 {
        true => 10,
        false => 20
    };

    println!("{} = {}", result1, convert1);
}
true = 10

A summary

Converting bools to i32 values in Rust is easy to do with a cast expression. But more complex or unusual conversions can be done with a match statement as well.