rustHow to check if a Rust HashMap contains a key?

To check if a Rust HashMap contains a key, you can use the contains_key method. This method takes a reference to the key as an argument and returns a boolean value indicating whether the key is present in the HashMap or not.

Example code

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert("key1", "value1");

if map.contains_key("key1") {
    println!("key1 is present in the HashMap");
}

Output example

key1 is present in the HashMap

Code explanation

• use std::collections::HashMap: imports the HashMap type from the standard library.
• let mut map = HashMap::new(): creates a new empty HashMap.
• map.insert("key1", "value1"): inserts a key-value pair into the HashMap.
• if map.contains_key("key1"): checks if the HashMap contains the specified key.
• println!("key1 is present in the HashMap"): prints a message if the key is present in the HashMap.

Helpful links

• Rust HashMap documentation

Edit this code on GitHub