std::basic_string_view<CharT,Traits>::find_first_of
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std::basic_string_view
(C++20)
(C++20)
(C++23)
basic_string_view::find_first_of
Constants
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Deduction guides (C++20)
constexpr size_type
find_first_of( basic_string_view v, size_type pos = 0 ) const noexcept;
(1)
(since C++17)
find_first_of( basic_string_view v, size_type pos = 0 ) const noexcept;
constexpr size_type
find_first_of( CharT ch, size_type pos = 0 ) const noexcept;
(2)
(since C++17)
find_first_of( CharT ch, size_type pos = 0 ) const noexcept;
constexpr size_type
find_first_of( const CharT* s, size_type pos, size_type count ) const;
(3)
(since C++17)
find_first_of( const CharT* s, size_type pos, size_type count ) const;
constexpr size_type
find_first_of( const CharT* s, size_type pos = 0 ) const;
(4)
(since C++17)
find_first_of( const CharT* s, size_type pos = 0 ) const;
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
v
-
view to search for
pos
-
position at which to start the search
count
-
length of the string of characters to search for
s
-
pointer to a string of characters to search for
ch
-
character to search for
[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
Run this code
#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() {}
[edit] See also
find first occurrence of characters
(public member function of
(public member function of
std::basic_string<CharT,Traits,Allocator>) [edit]