Iterators and closures

Focus: one iterator pipeline that filters, transforms, limits, and collects a score list.

Open in Playground 

entry top_scores(scores: u64[], min_score: u64, limit: u32) -> u64[] {
    return scores
        .iter()
        .filter(|score: u64| { return score >= min_score })
        .map(|score: u64| { return score * 10 })
        .take(limit)
        .collect()
}

How it works

• scores.iter() creates the lazy iterator pipeline.
• filter keeps only values greater than or equal to min_score.
• map applies a multiplier to each selected score.
• take(limit) bounds the amount of work before collect() materializes the array.
• collect() turns the lazy pipeline back into a u64[] return value.