Advanced Ranges and Views

Build lazy pipelines

auto top_scores = scores
    | std::views::filter([](int score) { return score >= 90; })
    | std::views::transform([](int score) { return score / 10; })
    | std::views::take(5);

Views are lazy and usually cheap to compose.

Projections with algorithms

std::ranges::sort(users, std::greater<>{}, &User::score);

Use projections to avoid small one-off lambdas when sorting or searching by a member.

Views are borrowed, not owned

• A view usually depends on another range staying alive.
• Materialize results into a container when you need stable storage.

Useful adaptors

• filter
• transform
• take
• drop
• keys
• values
• split

Practical guidance

• Keep pipelines readable; break them across lines.
• Avoid hidden work in predicates.
• Materialize at API boundaries when lifetime would otherwise be ambiguous.