rustHow to iterate through hashmap keys in Rust

Iterating through a HashMap in Rust can be done using the iter() method. This method returns an iterator over the key-value pairs of the HashMap. The following example code block shows how to iterate through the keys of a HashMap:

let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);

for (key, _) in map.iter() {
    println!("{}", key);
}

This code will output:

a
b
c

The code works by first creating a new HashMap and inserting three key-value pairs. Then, the iter() method is used to get an iterator over the key-value pairs. Finally, a for loop is used to iterate over the iterator and print out the keys.

Code explanation

1. let mut map = HashMap::new();: creates a new empty HashMap.
2. map.insert("a", 1);: inserts a key-value pair into the HashMap.
3. map.iter(): returns an iterator over the key-value pairs of the HashMap.
4. for (key, _) in map.iter(): iterates over the iterator and assigns the key to the key variable.
5. println!("{}", key);: prints out the key.

Helpful links

• HashMap documentation
• Iterator documentation

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