std::basic_string_view<CharT,Traits>::find_first_of

Since C++17

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

# Declarations

constexpr size_type
find_first_of( basic_string_view v, size_type pos = 0 ) const noexcept;

(since C++17)

constexpr size_type
find_first_of( CharT ch, size_type pos = 0 ) const noexcept;

(since C++17)

constexpr size_type
find_first_of( const CharT* s, size_type pos, size_type count ) const;

(since C++17)

constexpr size_type
find_first_of( const CharT* s, size_type pos = 0 ) const;

(since C++17)

# Parameters

# Return value

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

# Example

#include <string_view>
 
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() {}

# See also