Rust Program to Sort map by keys

Sort map by keys

Rust Programming Language

Problem

Rust program that sorts a map by its keys.

Input

use std::collections::BTreeMap;

fn main() {

    // Create a map with some key-value pairs

    let mut map = BTreeMap::new();

    map.insert("foo", 1);

    map.insert("bar", 2);

    map.insert("baz", 3);

    map.insert("qux", 4);

    // Print out the unsorted map

    println!("Unsorted map:");

    for (key, value) in &map {

        println!("{}: {}", key, value);

    }

    // Sort the map by its keys

    let sorted_map = map.into_iter().collect::<BTreeMap<_, _>>();

    // Print out the sorted map

    println!("Sorted map:");

    for (key, value) in &sorted_map {

        println!("{}: {}", key, value);

    }

}{codeBox}

Output

Unsorted map:

bar: 2

baz: 3

foo: 1

qux: 4

Sorted map:

bar: 2

baz: 3

foo: 1

qux: 4{codeBox}

Explanation

In this example, we use a BTreeMap instead of a regular HashMap because BTreeMap is a map implementation that keeps its keys in sorted order. We create a BTreeMap and insert some key-value pairs into it.

Next, we print out the unsorted map by iterating over its key-value pairs using a for loop and the println! macro.

Then, we sort the map by its keys by converting it into an iterator using into_iter, and then collecting the iterator into a new BTreeMap using the collect method. This creates a new BTreeMap with the same key-value pairs as the original map, but with the keys in sorted order.

Finally, we print out the sorted map by iterating over its key-value pairs using a for loop and the println! macro.

The unsorted map first, and then printing out the same map after it has been sorted by its keys. The order of the key-value pairs in the unsorted map is arbitrary, while the key-value pairs in the sorted map are sorted alphabetically by their keys.