rustHow to create enum from string in Rust

Enums in Rust can be created from strings using the FromStr trait. This trait is implemented for the str type, allowing us to convert a string into an enum. To do this, we must first define the enum and implement the FromStr trait for it. Then, we can use the str::parse method to convert a string into the enum.

use std::str::FromStr;

#[derive(Debug)]
enum Color {
    Red,
    Green,
    Blue,
}

impl FromStr for Color {
    type Err = ();

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s {
            "Red" => Ok(Color::Red),
            "Green" => Ok(Color::Green),
            "Blue" => Ok(Color::Blue),
            _ => Err(()),
        }
    }
}

fn main() {
    let color = "Green".parse::<Color>().unwrap();
    println!("{:?}", color);
}

Output example:

Green

Explanation

The FromStr trait is implemented for the str type, allowing us to convert a string into an enum. To do this, we must first define the enum and implement the FromStr trait for it. Then, we can use the str::parse method to convert a string into the enum. In the example above, we define an enum Color with three variants, and implement the FromStr trait for it. We then use the str::parse method to convert the string "Green" into the Color enum.

Helpful links

• Rust Documentation - FromStr
• Rust Documentation - str::parse
• Rust by Example - Enums

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