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

From cppreference.com
< cpp‎ | ranges‎ | split view
 
 
Ranges library
 
 
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)}.

[edit] Parameters

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

[edit] 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 splits = std::views::split (view, 0); // (2)
 for (const auto& split : splits)
 {
 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

[edit] 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

[edit] See also

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

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