quest – Rust: Collections

Core Beginner

05 Collections

Work with the two collections you'll reach for most: find a maximum safely, then tally word frequencies.

Step 2 / 2

Count occurrences of each word in word_count.

Hints

HashMap entry API: *map.entry(key).or_insert(0) += 1;

05_collections.rs

use std::collections::HashMap;

// count occurrences of each word
fn word_count(words: &[&str]) -> HashMap<String, u32> {
    todo!()
}

Reset to starterCompiled in a sandbox; hidden checks must pass.

Reveal solution

use std::collections::HashMap;

fn word_count(words: &[&str]) -> HashMap<String, u32> {
    let mut counts = HashMap::new();
    for w in words {
        *counts.entry(w.to_string()).or_insert(0) += 1;
    }
    counts
}