std::string_view find_last_of() method

since C++17

// (1) Const version only
constexpr size_type find_last_of( const basic_string& str, size_type pos = 0 ) const noexcept;

// (2) Const version only
constexpr size_type find_last_of( const CharT* s, size_type pos, size_type count ) const;

// (3) Const version only
constexpr size_type find_last_of( const CharT* s, size_type pos = 0 ) const;

// (4) Const version only
constexpr size_type find_last_of( CharT ch, size_type pos = 0 ) const noexcept;

Finds the last character equal to one of characters in the given character sequence. The search considers only the interval [ 0; pos ].

• (1) Finds the last occurence of any of the characters of v in this view, ending at position pos.
• (2) Equivalent to find_last_of(basic_string_view(std::addressof(c), 1), pos).
• (3) Equivalent to find_last_of(basic_string_view(s, count), pos).
• (4) Equivalent to find_last_of(basic_string_view(s), pos).

Parameters

• v - view to search for
• pos - position at which the search is to finish
• 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

Return value

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

Complexity

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

important

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Exceptions

(none)

Example

#include <string_view>
#include <iostream>
 
int main()
{
  using namespace std::literals;
  constexpr auto N = std::string_view::npos;
 
  static_assert(
    5 == "delete"sv.find_last_of("cdef"sv) &&
      //       └────────────────────┘
    N == "double"sv.find_last_of("fghi"sv) &&
      //
    0 == "else"sv.find_last_of("bcde"sv, 2 /* pos [0..2]: "els" */) &&
      //  └────────────────────────┘
    N == "explicit"sv.find_last_of("abcd"sv, 4 /* pos [0..4]: "expli" */) &&
      //
    3 == "extern"sv.find_last_of('e') &&
      //     └────────────────────┘
    N == "false"sv.find_last_of('x') &&
      //
    0 == "inline"sv.find_last_of('i', 2 /* pos [0..2]: "inl" */) &&
      //  └───────────────────────┘
    N == "mutable"sv.find_last_of('a', 2 /* pos [0..2]: "mut" */) &&
      //
    3 == "namespace"sv.find_last_of("cdef", 3 /* pos [0..3]: "name" */, 3 /* "cde" */) &&
      //     └─────────────────────────┘
    N == "namespace"sv.find_last_of("cdef", 3 /* pos [0..3]: "name" */, 2 /* "cd" */)
  );
 
  std::cout << "All tests passed.\n";
}

Output

All tests passed.