Rust Function: Parse string to integer

Last update on December 21 2024 10:19:48 (UTC/GMT +8 hours)

Write a Rust function that returns an Option representing the result of parsing a string into an integer.

Sample Solution:

Rust Code:

fn parse_string_to_integer(input: &str) -> Option<String> {
    match input.parse::<i32>() {
        Ok(parsed_int) => Some(parsed_int.to_string()),
        Err(_) => None,
    }
}

fn main() {
    let input = "150";
    match parse_string_to_integer(input) {
        Some(parsed) => println!("Parsed integer: {}", parsed),
        None => println!("Failed to parse integer"),
    }
}

Output:

Parsed integer: 150

Explanation:

Here's a brief explanation of the above Rust code:

• 'parse_string_to_integer' takes a string slice 'input' as input and attempts to parse it into an 'i32'.
• If parsing succeeds ('Ok(parsed_int)'), the function returns 'Some(parsed_int.to_string())', where 'parsed_int' is converted to a string.
• If parsing fails ('Err(_)'), the function returns 'None'.
• In the 'main' function, we call 'parse_string_to_integer' with a sample input string '"150"' and handle the result accordingly, printing the parsed integer if successful or a failure message if parsing fails.

Rust Code Editor:

Previous: Rust Result and Option types Exercises.
Next: Rust Function: Find maximum value.