26 Ranges library [ranges]

26.7 Range adaptors [range.adaptors]

26.7.13 Drop while view [range.drop.while] Overview [range.drop.while.overview]

Given a unary predicate pred and a view r, drop_while_view produces a view of the range [ranges​::​find_if_not(r, pred), ranges​::​end(r)).
The name views​::​drop_while denotes a range adaptor object ([range.adaptor.object]).
Given subexpressions E and F, the expression views​::​drop_while(E, F) is expression-equivalent to drop_while_view(E, F).
[Example 1: constexpr auto source = " \t \t \t hello there"sv; auto is_invisible = [](const auto x) { return x == ' ' || x == '\t'; }; auto skip_ws = views::drop_while(source, is_invisible); for (auto c : skip_ws) { cout << c; // prints hello there with no leading space } — end example]