环境

• Rust 1.56.1
• VSCode 1.61.2

概念

参考：https://doc.rust-lang.org/stable/rust-by-example/std/hash.html

示例

HashMap 和其它语言类型，存储键值对。

main.rs

use std::collections::HashMap;

fn call(number: &str) -> &str {
    match number {
        "798-1364" => {
            "We're sorry, the call cannot be completed as dialed. 
            Please hang up and try again."
        }
        "645-7689" => {
            "Hello, this is Mr. Awesome's Pizza. My name is Fred.
            What can I get for you today?"
        }
        _ => "Hi! Who is this again?",
    }
}

fn main() {
    let mut contacts = HashMap::new();

    contacts.insert("Daniel", "798-1364");
    contacts.insert("Ashley", "645-7689");
    contacts.insert("Katie", "435-8291");
    contacts.insert("Robert", "956-1745");

    match contacts.get("Daniel") {
        Some(&number) => println!("Calling Daniel: {}", call(number)),
        _ => println!("Don't have Daniel's number."),
    }

    contacts.remove("Ashley");
    for (contact, &number) in contacts.iter() {
        println!("Calling {}: {}", contact, call(number));
    }
}

总结

了解了 Rust 中标准库中的 HashMap 的使用。

附录