How to Iterate through the Values of an Enum in Rust

Created May 4, 2022 at 10:15

Modified May 4, 2022 at 16:26

Using a static array

If the enum is C-like, then you can create a static array of each of the variants and return an iterator of references to them:

use self::Direction::*;
use std::slice::Iter;

#[derive(Debug)]
pub enum Direction {
  North,
  South,
  East,
  West,
}

impl Direction {
  pub fn iterator() -> Iter<'static, Direction> {
    static DIRECTIONS: [Direction; 4] = [North, South, East, West];
    DIRECTIONS.iter()
  }
}

fn main() {
  for direction in Direction::iterator() {
    println!("{:?}", direction);
  }
}

North
South
East
West

Using strum Crate

Install

Add the following line to your Cargo.toml file:

[dependencies]
strum = "0.24"
strum_macros = "0.24"

# You can also use the "derive" feature, and import the macros directly from "strum"
# strum = { version = "0.24", features = ["derive"] }

Strum Usage

Strum is a set of macros and traits for working with enums and strings easier in Rust.

// You need to bring the trait into scope to use it!
use strum::IntoEnumIterator;
use strum_macros::EnumIter;

#[derive(Debug, EnumIter)]
pub enum Direction {
  North,
  South,
  East,
  West,
}

fn main() {
  for direction in Direction::iter() {
    println!("{:?}", direction);
  }
}