rustHow to use a Rust HashMap in a struct?

A Rust HashMap can be used in a struct by declaring a field of type HashMap<K, V> where K is the type of the key and V is the type of the value.

Example code

use std::collections::HashMap;

struct MyStruct {
    map: HashMap<String, i32>,
}

fn main() {
    let mut my_struct = MyStruct {
        map: HashMap::new(),
    };
    my_struct.map.insert("key".to_string(), 1);
    println!("{:?}", my_struct);
}

Output example

MyStruct { map: {"key": 1} }

Code explanation

1. use std::collections::HashMap;: This imports the HashMap type from the std::collections module.

2. map: HashMap<String, i32>: This declares a field of type HashMap<String, i32> in the MyStruct struct.

3. HashMap::new(): This creates a new empty HashMap instance.

4. my_struct.map.insert("key".to_string(), 1);: This inserts a key-value pair into the HashMap instance.

Helpful links

• Rust HashMap Documentation

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