map Create populated in Rust 1.55

In Rust, you can create a hash table using the HashMap data structure from the standard library. Here’s an example of how to create a HashMap with a String key and an i32 value:

use std::collections::HashMap;
fn main() {

    // Create a new HashMap

    let mut my_hash_map = HashMap::new();
// Insert key-value pairs into the HashMap

    my_hash_map.insert(String::from("Alice"), 32);

    my_hash_map.insert(String::from("Bob"), 27);

    my_hash_map.insert(String::from("Charlie"), 45);
// Access a value in the HashMap

    println!("Charlie's age is {}", my_hash_map.get("Charlie").unwrap());
// Update a value in the HashMap

    my_hash_map.insert(String::from("Bob"), 28);
// Remove a key-value pair from the HashMap

    my_hash_map.remove("Charlie");
// Iterate over the HashMap

    for (key, value) in &my_hash_map {

        println!("{} is {} years old", key, value);

    }

}

In the example above, we first import the HashMap struct from the collections module. We then create a new instance of HashMap by calling the new() method, and insert three key-value pairs into it using the insert() method. We can access a value in the HashMap using the get() method, and update a value using the insert() method with the same key.

We can remove a key-value pair from the HashMap using the remove() method, and iterate over all the key-value pairs using a for loop and the iter() method. Note that we use a reference to the HashMap in the for loop to avoid taking ownership of the structure.

This is a basic example, but the HashMap in Rust offers many more features and options for customization.