std::ranges::split_view<V,Pattern>::split_view

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< cpp‎ | ranges‎ | split view
 
C++
 
Ranges library
Range adaptors
 
std::ranges::split_view
 
Defined in header <ranges>
split_view()

    requires std::default_initializable<V> &&

             std::default_initializable<Pattern> = default;
 (1) (since C++20)
constexpr explicit split_view( V base, Pattern pattern );
 (2) (since C++20)
template< ranges::forward_range R >

    requires std::constructible_from<V, views::all_t<R>> &&
             std::constructible_from<Pattern, ranges::single_view<
                                                  ranges::range_value_t<R>>>

constexpr explicit split_view( R&& r, ranges::range_value_t<R> e );
 (3) (since C++20)

Constructs a split_view.

Let base_ be the underlying view and pattern_ be the delimiter.

1) Default constructor. Value-initializes base_ and pattern_ with their default member initializers respectively.
2) Initializes base_ with std::move(base) and pattern_ with std::move(pattern).
3) Initializes base_ with views::all(std::forward<R>(r)) and pattern_ with ranges::single_view{std::move(e)}.

Parameters

base - the view (to be split)
pattern - view to be used as the delimiter
e - element to be used as the delimiter

Example

Run this code
#include <algorithm>
#include <array>
#include <cctype>
#include <iostream>
#include <iterator>
#include <ranges>
#include <string_view>
#include <vector>
 
int main()
{
    {
        auto view = std::views::iota(1, 20)
                  | std::views::transform([](int x) { return x % 5; });
        auto splitts = std::views::split(view, 0); // (2)
        for (const auto& split : splitts)
        {
            std::cout << "{ ";
            std::ranges::copy(split, std::ostream_iterator<int>(std::cout, " "));
            std::cout << "} ";
        }
    }
    std::cout << '\n';
 
    {
        const std::vector nums{1, -1, -1, 2, 3, -1, -1, 4, 5, 6};
        const std::array delim{-1, -1};
        auto splitter = std::views::split(nums, delim); // (3)
        for (const auto& split : splitter)
        {
            std::cout << "{ ";
            std::ranges::copy(split, std::ostream_iterator<int>(std::cout, " "));
            std::cout << "} ";
        }
    }
    std::cout << '\n';
 
    {
        constexpr std::string_view JupiterMoons
        {
            "Callisto, Europa, Ganymede, Io, and 91 more"
        };
        constexpr std::string_view delim{", "};
        std::ranges::split_view moons_extractor{JupiterMoons, delim}; // (3)
        auto is_moon = std::views::filter([](auto str)
        {
            return std::isupper(str[0]);
        });
        std::cout << "Some moons of Jupiter: ";
        for (const auto moon : moons_extractor | is_moon)
            std::cout << std::string_view(moon) << ' ';
    }
    std::cout << '\n';
}

Output: 

{ 1 2 3 4 } { 1 2 3 4 } { 1 2 3 4 } { 1 2 3 4 }
{ 1 } { 2 3 } { 4 5 6 }
Some moons of Jupiter: Callisto Europa Ganymede Io

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 3714
(P2711R1) 		C++20 the multi-parameter constructor was not explicit made explicit

See also

 constructs a lazy_split_view
(public member function of std::ranges::lazy_split_view<V,Pattern>)
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