find the median of all keys in a map in rust

To find the median of all keys in a map in Rust, we can follow these steps:

1. Extract all keys from the map into a vector using the keys method.
2. Sort the vector of keys using the sort method in ascending order.
3. Calculate the length of the vector and check if it's even or odd.
4. If the length is even, we take the average of the middle two keys.
5. If the length is odd, we simply take the middle key.

Here's the Rust code to accomplish this:

main.rs
use std::collections::HashMap;

fn main() {
    let mut map = HashMap::new();
    map.insert(1, "one");
    map.insert(5, "five");
    map.insert(3, "three");
    map.insert(2, "two");
    map.insert(4, "four");

    let mut keys: Vec<_> = map.keys().cloned().collect();
    keys.sort();

    let len = keys.len();
    let median = if len % 2 == 0 {
        // Average of middle two keys
        let middle = len / 2;
        (keys[middle - 1] + keys[middle]) / 2
    } else {
        // Middle key
        keys[len / 2]
    };

    println!("Median: {}", median);
}
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In this example, we created a HashMap with integer keys and string values. Then we extracted all the keys from the map and sorted them. Finally, we calculated the median of the keys using the algorithm described above and printed the result.

Note that we first cloned the keys iterator to create a new vector with the keys from the map. This is because HashMap's keys method returns an iterator over references to the keys, which we cannot sort directly.