Question

I have two columns of data. For example,

[78, c]

[28, a]

[34, g]

I want to see whether any built-in function to sort the number and tell me the order information. For example, (from small to large) the function will return [2, 3, 1] because the 2nd row has the smallest 1st column element.

Answer 1

What is your data structure?

If you’re in C++/CLI, then you’ve got the entire .NET framework available to you.

That said, I don’t believe that there’s anything built-in that will tell you the order. I believe everything will actually do the sort.

If you really need the order, not a sorted list, I believe this will do it. This creates new objects that remember their original list position, sorts them, and then reads back what the original indexes were.

// I'm assuming you have a class similar to this already.
ref class MyData
{
public:
    int number;
    String^ letter;
};

ref class SortHelper : IComparable<SortHelper^>
{
public:
    MyData^ data;
    int originalIndex;

    SortHelper(MyData^ data, int index)
    {
        this->data = data;
        this->originalIndex = index;
    }

    virtual CompareTo(SortHelper^ other)
    {
        return this->data->number.CompareTo(other->data->number);
    }
};

void List<int> GetSortedIndexes(List<MyData>^ input)
{
    List<SortHelper>^ working = gcnew List<SortHelper>();
    for(int i = 0; i < input->Count; i++)
    {
        working->Add(gcnew SortHelper(input[i], i));
    }

    working->Sort();

    List<int>^ result = gcnew List<int>();        
    for each(SortHelper^ helper in working)
    {
        result->Add(helper->originalIndex);
    }

    return result;
}