Rust HashMap Iteration: Printing Key-Value pairs

Last update on December 21 2024 10:21:34 (UTC/GMT +8 hours)

Write a Rust program that iterate over a HashMap and print each key-value pair.

Sample Solution:

Rust Code:

use std::collections::HashMap; // Import the HashMap type from the standard library

fn main() {
    // Create a HashMap to store key-value pairs
    let mut my_map: HashMap<&str, i32> = HashMap::new(); // Key: &str (string slice), Value: i32

    // Insert some key-value pairs into the HashMap
    my_map.insert("a", 1);
    my_map.insert("b", 2);
    my_map.insert("c", 3);

    // Iterate over the HashMap and print each key-value pair
    for (key, value) in &my_map {
        println!("Key: {}, Value: {}", key, value);
    }
}

Output:

Key: c, Value: 3
Key: b, Value: 2
Key: a, Value: 1

Explanation:

Here is a brief explanation of the above Rust code:

• use std::collections::HashMap;: This line imports the "HashMap" type from the standard library, allowing us to use HashMaps in our code.
• fn main() { ... }: This line defines the main function, which is the entry point of the Rust program.
• let mut my_map: HashMap<&str, i32> = HashMap::new();: This line creates an empty HashMap named 'my_map' with keys of type '&str' (string slice) and values of type i32.
• my_map.insert("a", 1);: This line inserts a key-value pair into the 'my_map' HashMap, where the key is the string slice "a" and the value is the integer 1. Similar lines insert additional key-value pairs.
• for (key, value) in &my_map { ... }: This line starts a loop to iterate over each key-value pair in the my_map HashMap. The loop iterates using a reference to the HashMap (&my_map), and each iteration unpacks the key and value into variables 'key' and 'value'.
• println!("Key: {}, Value: {}", key, value);: This line prints each key-value pair to the console. The key and value are interpolated into the string using {} placeholders.

Rust Code Editor:

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