Composing Views

Chain multiple views to create complex data transformations

Example Code

cpp

#include <ranges>
#include <vector>
#include <iostream>
#include <string>
int main() {
    std::vector<int> numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    
    // Compose multiple views: filter -> transform -> take
    auto pipeline = numbers
        | std::views::filter([](int n) { return n % 2 == 0; })  // Keep even
        | std::views::transform([](int n) { return n * n; })     // Square them
        | std::views::take(3);                                    // First 3
    
    std::cout << "Result: ";
    for (int n : pipeline) {
        std::cout << n << " ";  // Output: 4 16 36
    }
    std::cout << std::endl;
    
    // String processing example
    std::string text = "  Hello, World!  ";
    auto words = text 
        | std::views::split(' ')
        | std::views::filter([](auto word) { 
            return !std::ranges::empty(word); 
          });
    
    return 0;
}

Explanation

Views can be composed into pipelines where each view transforms the data. The entire pipeline is lazy - elements are processed one at a time as they're consumed, making it memory-efficient.

Key Points

1filter - keep elements matching predicate
2transform - apply function to each element
3take/drop - limit or skip elements
4Pipelines are evaluated lazily