rustHow to use a tuple as a key in a Rust HashMap?

Tuples can be used as keys in a Rust HashMap by implementing the Hash and Eq traits. This can be done by using the #[derive(Hash, Eq)] annotation on the tuple struct.

#[derive(Hash, Eq)]
struct TupleStruct(i32, i32);

use std::collections::HashMap;

let mut map = HashMap::new();

let key = TupleStruct(1, 2);

map.insert(key, "value");

The example code above creates a tuple struct TupleStruct with two i32 fields, and implements the Hash and Eq traits on it. Then, a HashMap is created and a key is created from the TupleStruct. Finally, the key is used to insert a value into the HashMap.

• #[derive(Hash, Eq)]: Annotation to implement the Hash and Eq traits on a tuple struct.
• TupleStruct(i32, i32): Tuple struct with two i32 fields.
• HashMap::new(): Creates a new HashMap.
• let key = TupleStruct(1, 2): Creates a key from the TupleStruct.
• map.insert(key, "value"): Inserts a value into the HashMap using the key.

Helpful links

• Rust HashMap Documentation
• Rust Derive Documentation

Edit this code on GitHub