rustHow to use enum as hashmap key in Rust
Enums in Rust can be used as hashmap keys by implementing the Eq
and Hash
traits. This can be done by adding #[derive(Eq, Hash)]
to the enum definition. For example:
#[derive(Eq, Hash)]
enum Color {
Red,
Blue,
Green,
}
fn main() {
use std::collections::HashMap;
let mut colors = HashMap::new();
colors.insert(Color::Red, "red");
colors.insert(Color::Blue, "blue");
colors.insert(Color::Green, "green");
println!("{:?}", colors);
}
The output of this code is {Color::Red: "red", Color::Blue: "blue", Color::Green: "green"}
. The #[derive(Eq, Hash)]
annotation allows the enum to be used as a key in the hashmap.
Helpful links
Related
More of Rust
- How to replace a capture group using Rust regex?
- How to convert a Rust slice of u8 to u32?
- Regex example to match multiline string in Rust?
- How to use regex to match a double quote in Rust?
- How to use non-capturing groups in Rust regex?
- How to match the end of a line in a Rust regex?
- How to clear a Rust HashMap?
- Yield example in Rust
- How to perform matrix operations in Rust?
- How to create a nested HashMap in Rust?
See more codes...