map Include in Rust 1.55

In Rust, you can check if a hash (also known as a hashmap) includes a key using the contains_key method.

Here's an example:

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

    let mut map = HashMap::new();

    

    // Insert some key-value pairs

    map.insert("apple", 3);

    map.insert("banana", 2);

    map.insert("cherry", 5);

    

    // Check if the hash includes the key "banana"

    if map.contains_key("banana") {

        println!("The hash includes the key 'banana'");

    }

    

    // Check if the hash includes the key "pear"

    if !map.contains_key("pear") {

        println!("The hash does not include the key 'pear'");

    }

}

In this example, we create a HashMap and insert some key-value pairs. Then, we use contains_key to check if the hash includes the keys "banana" and "pear", and print a message accordingly.

Note that contains_key returns a bool value indicating whether the key is present in the hash or not.