std::string_view contains() method

od C++23

// (1) Const version only
constexpr bool contains( basic_string_view sv ) const noexcept;

// (2) Const version only
constexpr bool contains( CharT c ) const noexcept;

// (3) Const version only
constexpr bool contains( const CharT* s ) const;

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 effectively do

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 view contains the provided substring, false otherwise.

Complexity

important

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Notes

Feature testing macro: __cpp_lib_string_view_contains.

Example

#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