rustHow to convert a Rust HashMap to JSON?

Converting a Rust HashMap to JSON can be done using the serde crate. serde provides a Serialize trait which can be used to serialize a Rust data structure into a JSON string.

Example code

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
struct Person {
    name: String,
    age: u8,
}

fn main() {
    let mut map = std::collections::HashMap::new();
    map.insert("John", Person {
        name: "John".to_string(),
        age: 30,
    });
    map.insert("Alice", Person {
        name: "Alice".to_string(),
        age: 25,
    });

    let json = serde_json::to_string(&map).unwrap();
    println!("{}", json);
}

Output example

{"John":{"name":"John","age":30},"Alice":{"name":"Alice","age":25}}

Code explanation

1. use serde::{Serialize, Deserialize};: This imports the Serialize and Deserialize traits from the serde crate.

2. #[derive(Serialize, Deserialize)]: This derives the Serialize and Deserialize traits for the Person struct.

3. let json = serde_json::to_string(&map).unwrap();: This uses the serde_json crate to serialize the map into a JSON string.

4. println!("{}", json);: This prints the JSON string to the console.

Helpful links

• serde
• serde_json

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