std::basic_string<CharT,Traits,Allocator>::find_last_of
| (1) | ||
size_type find_last_of( const basic_string& str,
size_type pos = npos ) const; |
(until C++11) | |
constexpr size_type find_last_of( const basic_string& str,
size_type pos = npos ) const noexcept; |
(since C++11) (until C++20) |
|
| (2) | ||
size_type find_last_of( const CharT* s,
size_type pos, size_type count ) const; |
(until C++11) | |
constexpr size_type find_last_of( const CharT* s,
size_type pos, size_type count ) const; |
(since C++11) | |
| (3) | ||
size_type find_last_of( const CharT* s, size_type pos = npos ) const; |
(until C++20) | |
constexpr size_type find_last_of( const CharT* s, size_type pos = npos ) const; |
(since C++20) | |
| (4) | ||
size_type find_last_of( CharT ch, size_type pos = npos ) const; |
(until C++11) | |
size_type find_last_of( CharT ch, size_type pos = npos ) const noexcept; |
(since C++11) (until C++20) |
|
constexpr size_type find_last_of( CharT ch,
size_type pos = npos ) const noexcept; |
(since C++20) | |
| (5) | ||
template < class StringViewLike >
size_type
find_last_of( const StringViewLike& t,
size_type pos = npos ) const noexcept(/* see below */); |
(since C++17) (until C++20) |
|
template < class StringViewLike >
constexpr size_type
find_last_of( const StringViewLike& t,
size_type pos = npos ) const noexcept(/* see below */); |
(since C++20) |
Finds the last character equal to one of characters in the given character sequence. The exact search algorithm is not specified. The search considers only the interval [0, pos]. If the character is not present in the interval, npos will be returned.
1) Finds the last character equal to one of characters in
str.
2) Finds the last character equal to one of characters in range
[s, s+count). This range can include null characters.
3) Finds the last character equal to one of characters in character string pointed to by
s. The length of the string is determined by the first 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 one of characters in
sv. 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.
In all cases, equality is checked by calling Traits::eq.
Parameters
| str | - | string identifying characters to search for |
| pos | - | position at which the search is to finish |
| 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 found character or npos if no such character is found.
Exceptions
5)
noexcept specification:
noexcept(std::is_nothrow_convertible_v<const T&, std::basic_string_view<CharT, Traits>>)
Example
#include<string>
#include<iostream>
int main()
{
const std::string path="/root/config";
auto const pos=path.find_last_of('/');
const auto leaf=path.substr(pos+1);
std::cout << leaf << '\n';
}
Output:
config
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2064 | C++11 | overload (3) and (4) were noexcept | removed |
| LWG 2946 | C++17 | string_view overload causes ambiguity in some cases |
avoided by making it a template |
| P1148R0 | C++11 C++17 |
noexcept for overload (4)/(5) was accidently dropped by LWG2064/LWG2946 | restored |
See also
| find characters in the string (public member function) |
|
| find the last occurrence of a substring (public member function) |
|
| find first occurrence of characters (public member function) |
|
| find first absence of characters (public member function) |
|
| find last absence of characters (public member function) |
|
|
(C++17)
|
find last occurrence of characters (public member function of std::basic_string_view<CharT,Traits>) |
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