std::basic_string_view<CharT,Traits>::contains

 

C++

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Standard library headers

Named requirements

Feature test macros (C++20)

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Concepts library (C++20)

Metaprogramming library (C++11)

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Ranges library (C++20)

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Technical specifications

Symbols index

External libraries

 

Strings library

Null-terminated strings

Byte strings

Multibyte strings

Wide strings

Classes

basic_string

basic_string_view (C++17)

char_traits

 

std::basic_string_view

Member functions basic_string_view::basic_string_view    basic_string_view::operator= Iterators basic_string_view::beginbasic_string_view::cbegin basic_string_view::endbasic_string_view::cend basic_string_view::rbeginbasic_string_view::crbegin basic_string_view::rendbasic_string_view::crend Element access basic_string_view::at basic_string_view::operator[] basic_string_view::front basic_string_view::back basic_string_view::data Capacity basic_string_view::sizebasic_string_view::length basic_string_view::max_size basic_string_view::empty Modifiers basic_string_view::remove_prefix basic_string_view::remove_suffix basic_string_view::swap

Operations basic_string_view::copy basic_string_view::substr basic_string_view::compare basic_string_view::starts_with (C++20) basic_string_view::ends_with (C++20) basic_string_view::contains (C++23) basic_string_view::find basic_string_view::rfind basic_string_view::find_first_of basic_string_view::find_last_of basic_string_view::find_first_not_of basic_string_view::find_last_not_of Constants basic_string_view::npos Non-member functions operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20) operator<< operator""sv Helper classes hash<std::string_view>hash<std::wstring_view>hash<std::u8string_view>hash<std::u16string_view>hash<std::u32string_view> (C++20) Deduction guides(C++20)

 

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.

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:

__cpp_lib_string_contains

Example

Run this code

#include <iostream>
#include <string_view>
 
auto main() -> int
{
    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") << ' ' // false
        << '\n';
}

Output:

true false true false true false

See also

starts_with (C++20)	checks if the string view starts with the given prefix (public member function)
ends_with (C++20)	checks if the string view ends with the given suffix (public member function)
find (C++17)	find characters in the view (public member function)
substr (C++17)	returns a substring (public member function)
contains (C++23)	checks if the string contains the given substring or character (public member function of std::basic_string<CharT,Traits,Allocator>)