convert string to i32 in rust

To convert a string to an i32 integer in Rust, you can use the parse method that is available on any std::str::FromStr type. Here's an example of how to do it:

main.rs
fn main() {
    let my_string = "42";
    let my_int = my_string.parse::<i32>().unwrap();
    println!("{}", my_int);
}
120 chars
6 lines

In this example, "42" is a string literal. We then call the parse method on this string by appending .parse::<i32>(). The ::<i32> part is a type hint to the compiler, telling it that we want to parse this string as an i32 integer. The unwrap method is used to get the actual value out of the Result type that parse returns. After this conversion, my_int will contain the value 42.

Note that the parse method returns a Result type, which can represent either success (Ok) or failure (Err). In the example above, we simply call unwrap to get the value out of the Ok variant. However, in a real program, it is important to handle the Err case gracefully.