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rustHow to loop through a Rust HashMap?

Looping through a Rust HashMap can be done using the iter() method. This method returns an iterator over the key-value pairs of the map. The following example code block shows how to loop through a HashMap and print out the key-value pairs:

use std::collections::HashMap;

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

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

Output example

a: 1
b: 2
c: 3

The code above consists of the following parts:

  1. use std::collections::HashMap; - imports the HashMap type from the std::collections module.
  2. let mut map = HashMap::new(); - creates a new empty HashMap and stores it in the map variable.
  3. map.insert("a", 1); - inserts a key-value pair into the map variable.
  4. for (key, value) in map.iter() { - starts a loop over the key-value pairs of the map variable.
  5. println!("{}: {}", key, value); - prints out the key-value pairs.

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