Modern way to filter STL container?

Question

Coming back to C++ after years of C# I was wondering what the modern - read: C++11 - way of filtering an array would be, i.e. how can we achieve something similar to this Li

Answer 1

In C++20, use filter view from the ranges library: (requires #include )

// namespace views = std::ranges::views;
vec | views::filter([](int a){ return a % 2 == 0; })

lazily returns the even elements in vec.

(See [range.adaptor.object]/4 and [range.filter])

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This is already supported by GCC 10 (live demo). For Clang and older versions of GCC, the original range-v3 library can be used too, with #include (or #include ) and the ranges::views namespace instead of std::ranges::views (live demo).