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

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< cpp‎ | 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

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

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