Selecting item in nested list.

Hi,

I have a question below:

This kind of situation occurs me from time to time an mapping one list to nested one makes the script reading confusing as I usually introduce 3rd list that looks like this:

List<int[]> mapping = new List<int[]>{ new int[2]{0,0},new int[2]{0,1} ... new int[2]{n,n} };

When first integer is index of list index, and second integer is index of element inside list.

When I want to select 5th element from nested list it looks like this:

Object NthElement = NestedList[ mapping[5][0] ] mapping[5][1];

Any suggestions for selecting nth element from nested list without introducing this mapping thing would be very helpful.

Thank you.

Replies to This Discussion

Permalink Reply by John on January 30, 2017 at 6:44am

Thank you for a reply.

I was also thinking datatrees.

And for general c#. The similar solution would be only something like dictionaries?

Permalink Reply by John on February 15, 2017 at 3:35am

Following your example:

DataTree<int> tree = new DataTree<int>();
tree.Add(0, new GH_Path(0));

tree.Add(1, new GH_Path(0));
tree.Add(2, new GH_Path(1));

tree.Add(3, new GH_Path(1));

What I want to know is what is the index of tree.Branch(1)[0] in a flattened list, which is 2 in this case?

It looks like the only way to know the index of tree.Branch(1)[0] in a flattened list which is 2 in this case. Is to loop through each branch and count items like this:

int count = 0;
for (int i = 0; i < tree.BranchCount; i++)
{
for (int j = 0; j < tree.Branch(i).Count; j++){

Rhino.RhinoApp.WriteLine( (count + j).ToString() + "index of datatree in a flattened list" );

}

count += v.Branch(i).Count; //Count indexes in a "flattened list" I was looking for this property but it seems that it is possible to do this through looping

}

if there is a property to know the index without counting, it would be good to know.

But then how dataTrees are better from simple arrays?

Permalink Reply by John on February 15, 2017 at 6:13am

The only thing I would like to do:

I have a datatree or array.

And I know an item indices for instance: tree.Branch(i)[j]

The property or method I am searching for is how to know index of item in a flattened list when knowing only i and j indices in array.

Looping is confusing, but works well after multiple tries.

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