Query a Rust HashMap by struct as key

get_by_struct.rs

// get by struct
use std::collections::HashSet;

#[derive(Hash, Eq, PartialEq, Debug)]
struct City {
    name: String,
    population: usize,
}

fn main() {
    let mut cities = HashSet::new();

    cities.insert(City {
        name: "San Francisco".to_string(),
        population: 884_363,
    });
    cities.insert(City {
        name: "Tokyo".to_string(),
        population: 9_273_000,
    });
    cities.insert(City {
        name: "Hong Kong".to_string(),
        population: 7_392_000,
    });

    println!(
        "{:#?}",
        &cities.get(&City {
            name: "San Francisco".to_string(),
            population: 884_363
        })
    );
}