Difference between revisions of "cpp/string/basic string view/contains"
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< cpp | string | basic string view
m (→Notes: +s) |
Andreas Krug (Talk | contribs) m (auto main() -> int -> int main()) |
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| Line 1: | Line 1: | ||
| − | {{cpp/string/basic_string_view/title | contains}} | + | {{cpp/string/basic_string_view/title|contains}} |
{{cpp/string/basic_string_view/navbar}} | {{cpp/string/basic_string_view/navbar}} | ||
{{dcl begin}} | {{dcl begin}} | ||
| − | {{dcl | num=1 |since=c++23|1= | + | {{dcl|num=1|since=c++23|1= |
constexpr bool contains( basic_string_view sv ) const noexcept; | constexpr bool contains( basic_string_view sv ) const noexcept; | ||
}} | }} | ||
| − | {{dcl | num=2 |since=c++23|1= | + | {{dcl|num=2|since=c++23|1= |
constexpr bool contains( CharT c ) const noexcept; | constexpr bool contains( CharT c ) const noexcept; | ||
}} | }} | ||
| − | {{dcl | num=3 |since=c++23|1= | + | {{dcl|num=3|since=c++23|1= |
constexpr bool contains( const CharT* s ) const; | constexpr bool contains( const CharT* s ) const; | ||
}} | }} | ||
| Line 22: | Line 22: | ||
===Parameters=== | ===Parameters=== | ||
{{par begin}} | {{par begin}} | ||
| − | {{par | sv | a string view}} | + | {{par|sv|a string view}} |
| − | {{par | c | a single character}} | + | {{par|c|a single character}} |
| − | {{par | s | a null-terminated character string}} | + | {{par|s|a null-terminated character string}} |
{{par end}} | {{par end}} | ||
| Line 34: | Line 34: | ||
===Example=== | ===Example=== | ||
| − | {{example | | + | {{example| |
| − | + | |code= | |
#include <iostream> | #include <iostream> | ||
#include <string_view> | #include <string_view> | ||
| − | + | int main() | |
{ | { | ||
using namespace std::literals; | using namespace std::literals; | ||
| Line 55: | Line 55: | ||
// bool contains(const CharT* x) const; | // bool contains(const CharT* x) const; | ||
| − | << std::string_view("basic_string_view").contains("string") << ' ' // true | + | << std::string_view("basic_string_view").contains("string") << ' ' // true |
| − | << std::string_view("basic_string_view").contains("String") << ' ' // false | + | << std::string_view("basic_string_view").contains("String") << '\n'; // false |
| − | + | ||
} | } | ||
| − | + | |output= | |
true false true false true false | true false true false true false | ||
}} | }} | ||
| Line 65: | Line 64: | ||
===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/string/basic_string_view/dsc starts_with}} | + | {{dsc inc|cpp/string/basic_string_view/dsc starts_with}} |
| − | {{dsc inc | cpp/string/basic_string_view/dsc ends_with}} | + | {{dsc inc|cpp/string/basic_string_view/dsc ends_with}} |
| − | {{dsc inc | cpp/string/basic_string_view/dsc find}} | + | {{dsc inc|cpp/string/basic_string_view/dsc find}} |
| − | {{dsc inc | cpp/string/basic_string_view/dsc substr}} | + | {{dsc inc|cpp/string/basic_string_view/dsc substr}} |
| − | {{dsc inc | cpp/string/basic_string/dsc {{SUBPAGENAMEE}}}} | + | {{dsc inc|cpp/string/basic_string/dsc {{SUBPAGENAMEE}}}} |
{{dsc end}} | {{dsc end}} | ||
{{langlinks|de|es|fr|it|ja|pl|pt|ru|zh}} | {{langlinks|de|es|fr|it|ja|pl|pt|ru|zh}} | ||
Revision as of 23:40, 3 June 2023
| constexpr bool contains( basic_string_view sv ) const noexcept; |
(1) | (since C++23) |
| constexpr bool contains( CharT c ) const noexcept; |
(2) | (since C++23) |
| constexpr bool contains( const CharT* s ) const; |
(3) | (since C++23) |
Checks if the string view contains the given substring, where
1) the substring is a string view.
2) the substring is a single character.
3) the substring is a null-terminated character string.
All three overloads are equivalent to return find(x) != npos;, where x is the parameter.
Contents |
Parameters
| sv | - | a string view |
| c | - | a single character |
| s | - | a null-terminated character string |
Return value
true if the string view contains the provided substring, false otherwise.
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_string_contains |
202011L | (C++23) | contains functions
|
Example
Run this code
#include <iostream> #include <string_view> int main() { using namespace std::literals; std::cout << std::boolalpha // bool contains(basic_string_view x) const noexcept; << "https://cppreference.com"sv.contains("cpp"sv) << ' ' // true << "https://cppreference.com"sv.contains("java"sv) << ' ' // false // bool contains(CharT x) const noexcept; << "C++23"sv.contains('+') << ' ' // true << "C++23"sv.contains('-') << ' ' // false // bool contains(const CharT* x) const; << std::string_view("basic_string_view").contains("string") << ' ' // true << std::string_view("basic_string_view").contains("String") << '\n'; // false }
Output:
true false true false true false
See also
| (C++20) |
checks if the string view starts with the given prefix (public member function) |
| (C++20) |
checks if the string view ends with the given suffix (public member function) |
| find characters in the view (public member function) | |
| returns a substring (public member function) | |
| (C++23) |
checks if the string contains the given substring or character (public member function of std::basic_string<CharT,Traits,Allocator>)
|
