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std::string find_last_not_of() method

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

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

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

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

// (5) Const version only
template < class StringViewLike >
constexpr size_type find_last_not_of( const StringViewLike& t, size_type pos = 0 ) const noexcept(/* see below */);

Finds the last character equal to none of the characters in the given character sequence.
The search considers only the interval [ 0, pos ].

  • (1) Finds the last character equal to none of the characters in str.

  • (2) Finds the last character equal to none of the characters in the range [ s, s + count ).
    This range can include null characters.

  • (3) Finds the last character equal to none of the characters in character string pointed to by s.
    The length of the string is determined by the last null character using Traits::length(s).

  • (4) Finds the last character equal to ch.

  • (5) Implicitly converts t to a string view sv as if by std::basic_string_view<CharT, Traits> sv = t;, then finds the last character equal to none of the characters in sv.

    Overload Resolution

    This overload participates in overload resolution only if std::is_convertible_v<const StringViewLike&, std::basic_string_view<CharT, Traits>> is true and std::is_convertible_v<const StringViewLike&, const CharT*> is false.

Parameters​

  • str - string identifying characters to search for
  • pos - position at which to start the search
  • count - length of character string identifying characters to search for
  • s - pointer to a character string identifying characters to search for
  • ch - character to search for
  • t - object (convertible to std::basic_string_view) identifying characters to search for

Return value​

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

Complexity​

important

This section requires improvement. You can help by editing this doc page.

Exceptions​

  • (1-4) (none)
  • (5) noexcept specification: 
    noexcept(std::is_nothrow_convertible_v<const T&, std::basic_string_view<CharT, Traits>>)

Notes​

Traits::eq() is used for comparison. By default Traits is std::char_traits<CharT>.

Example​

#include <iostream>
#include <string>
 
void show_pos(const std::string& str, std::string::size_type found)
{
    if (found != std::string::npos)
        std::cout << "[" << found << "] = \'" << str[found] << "\'\n";
    else
        std::cout << "not found" "\n";
}
 
int main()
{
    std::string str{"abc_123"};
    char const* skip_set{"0123456789"};
    std::string::size_type str_last_pos{std::string::npos};
 
    show_pos(str, str.find_last_not_of(skip_set)); // [3] = '_'
 
    str_last_pos = 2;
    show_pos(str, str.find_last_not_of(skip_set, str_last_pos)); // [2] = 'c'
 
    str_last_pos = 2;
    show_pos(str, str.find_last_not_of('c', str_last_pos)); // [1] = 'b'
 
    const char arr[]{'3', '4', '5'};
    show_pos(str, str.find_last_not_of(arr)); // [5] = '2'
 
    str_last_pos = 2;
    std::string::size_type skip_set_size{4};
    show_pos(str, str.find_last_not_of(skip_set,
                                       str_last_pos,
                                       skip_set_size)); // [2] = 'c'
 
    show_pos(str, str.find_last_not_of("abc")); // [6] = '3'
 
    str_last_pos = 2;
    show_pos(str, str.find_last_not_of("abc", str_last_pos)); // not found
}
Output
[3] = '_'
[2] = 'c'
[1] = 'b'
[5] = '2'
[2] = 'c'
[6] = '3'
not found
This article originates from this CppReference page. It was likely altered for improvements or editors' preference. Click "Edit this page" to see all changes made to this document.
Hover to see the original license.

std::string find_last_not_of() method

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

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

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

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

// (5) Const version only
template < class StringViewLike >
constexpr size_type find_last_not_of( const StringViewLike& t, size_type pos = 0 ) const noexcept(/* see below */);

Finds the last character equal to none of the characters in the given character sequence.
The search considers only the interval [ 0, pos ].

  • (1) Finds the last character equal to none of the characters in str.

  • (2) Finds the last character equal to none of the characters in the range [ s, s + count ).
    This range can include null characters.

  • (3) Finds the last character equal to none of the characters in character string pointed to by s.
    The length of the string is determined by the last null character using Traits::length(s).

  • (4) Finds the last character equal to ch.

  • (5) Implicitly converts t to a string view sv as if by std::basic_string_view<CharT, Traits> sv = t;, then finds the last character equal to none of the characters in sv.

    Overload Resolution

    This overload participates in overload resolution only if std::is_convertible_v<const StringViewLike&, std::basic_string_view<CharT, Traits>> is true and std::is_convertible_v<const StringViewLike&, const CharT*> is false.

Parameters​

  • str - string identifying characters to search for
  • pos - position at which to start the search
  • count - length of character string identifying characters to search for
  • s - pointer to a character string identifying characters to search for
  • ch - character to search for
  • t - object (convertible to std::basic_string_view) identifying characters to search for

Return value​

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

Complexity​

important

This section requires improvement. You can help by editing this doc page.

Exceptions​

  • (1-4) (none)
  • (5) noexcept specification: 
    noexcept(std::is_nothrow_convertible_v<const T&, std::basic_string_view<CharT, Traits>>)

Notes​

Traits::eq() is used for comparison. By default Traits is std::char_traits<CharT>.

Example​

#include <iostream>
#include <string>
 
void show_pos(const std::string& str, std::string::size_type found)
{
    if (found != std::string::npos)
        std::cout << "[" << found << "] = \'" << str[found] << "\'\n";
    else
        std::cout << "not found" "\n";
}
 
int main()
{
    std::string str{"abc_123"};
    char const* skip_set{"0123456789"};
    std::string::size_type str_last_pos{std::string::npos};
 
    show_pos(str, str.find_last_not_of(skip_set)); // [3] = '_'
 
    str_last_pos = 2;
    show_pos(str, str.find_last_not_of(skip_set, str_last_pos)); // [2] = 'c'
 
    str_last_pos = 2;
    show_pos(str, str.find_last_not_of('c', str_last_pos)); // [1] = 'b'
 
    const char arr[]{'3', '4', '5'};
    show_pos(str, str.find_last_not_of(arr)); // [5] = '2'
 
    str_last_pos = 2;
    std::string::size_type skip_set_size{4};
    show_pos(str, str.find_last_not_of(skip_set,
                                       str_last_pos,
                                       skip_set_size)); // [2] = 'c'
 
    show_pos(str, str.find_last_not_of("abc")); // [6] = '3'
 
    str_last_pos = 2;
    show_pos(str, str.find_last_not_of("abc", str_last_pos)); // not found
}
Output
[3] = '_'
[2] = 'c'
[1] = 'b'
[5] = '2'
[2] = 'c'
[6] = '3'
not found
This article originates from this CppReference page. It was likely altered for improvements or editors' preference. Click "Edit this page" to see all changes made to this document.
Hover to see the original license.