Converting a String to int in Rust
Alex Garella
8th September 2023
Data conversions are an integral part of programming. If you're wondering how to convert a String to an int in Rust, you're in the right place.
Using the parse Method
Rust provides the parse() method, which tries to convert a String to a specified data type.
fn main() {
let s: String = "42".to_string();
let number: i32 = s.parse().expect("Not a valid number");
println!("{}", number); // Outputs: 42
}
Note: We've used expect() for simplicity, but in real-world code, you'd handle the Result more gracefully.
Error Handling with parse
The parse() method returns a Result, which can be an Ok(T) or an Err. To handle potential errors:
fn main() {
let s = "42a".to_string();
match s.parse::<i32>() {
Ok(n) => println!("Number: {}", n),
Err(e) => println!("Error: {}", e),
}
}
// Outputs: Error: invalid digit found in string
Conclusion
Converting a String to an int in Rust is straightforward using the parse() method. By leveraging Rust's powerful error handling mechanism, you ensure safe and predictable conversions.