CODEWITHSUNDEEP
c++
bonnoz05
bonnoz05

Reputation: 17

C++ Concatenate attributes of two vectors of different type into new vector

I have two vectors as follows:

std::vector<Foo> v1;
std::vector<Bar> v2;

both Foo and Bar possess the .baz attribute, for example of type int.

What I would like is to end up with a new vector, combining all .baz attributes, in order:

std::vector<int> v3;

where v3.size() == v1.size() + v2.size()

Is there a succinct way of achieving this?

Upvotes: 1

Views: 196

Answers (2)

Jarod42
Jarod42

Reputation: 217283

With range-v3, it might be:

std::vector<int> v3 = ranges::view::concat(ranges::view::transform(v1, &Foo::baz),
                                           ranges::view::transform(v2, &Bar::baz));

Demo

Upvotes: 2

Xirema
Xirema

Reputation: 20396

I don't know that you need something more succinct than simply:

int main() {
    std::vector<Foo> foos = get_foos();
    std::vector<Bar> bars = get_bars();

    std::vector<int> vec;
    auto merge = [](auto const& arg) {return arg.baz;};
    std::transform(foos.begin(), foos.end(), std::back_inserter(vec), merge);
    std::transform(bars.begin(), bars.end(), std::back_inserter(vec), merge);
}

Upvotes: 6

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