std::basic_string_view<CharT,Traits>::find_first_of - cppreference.com (original) (raw)

Finds the first character equal to any of the characters in the given character sequence.

1. Finds the first occurrence of any of the characters of v in this view, starting at position pos.

2. Equivalent to find_first_of(basic_string_view(std::addressof(ch), 1), pos).

3. Equivalent to find_first_of(basic_string_view(s, count), pos).

4. Equivalent to find_first_of(basic_string_view(s), pos).

[edit] Parameters

[edit] Return value

Position of the first occurrence of any character of the substring, or npos if no such character is found.

[edit] Complexity

O(size() * v.size()) at worst.

[edit] Example

#include   using namespace std::literals; constexpr auto N = std::string_view::npos;   constexpr bool is_white_space(const char c) { return " \t\n\f\r\v"sv.find_first_of(c) != N; };   static_assert( 1 == "alignas"sv.find_first_of("klmn"sv) && // └─────────────────────────┘ N == "alignof"sv.find_first_of("wxyz"sv) && // 3 == "concept"sv.find_first_of("bcde"sv, /* pos= / 1) && // └───────────────────────┘ N == "consteval"sv.find_first_of("oxyz"sv, / pos= / 2) && // 6 == "constexpr"sv.find_first_of('x') && // └─────────────────────┘ N == "constinit"sv.find_first_of('x') && // 6 == "const_cast"sv.find_first_of('c', / pos= / 4) && // └──────────────────────┘ N == "continue"sv.find_first_of('c', / pos= / 42) && // 5 == "co_await"sv.find_first_of("cba", / pos= / 4) && // └───────────────────────┘ 7 == "decltype"sv.find_first_of("def", / pos= / 2, / count= / 2) && // └────────────────────┘ N == "decltype"sv.find_first_of("def", / pos= / 2, / count= */ 1) && // is_white_space(' ') && is_white_space('\r') && !is_white_space('\a') );   int main() {}

[edit] See also