Manipulate Lists/Array

RE: Manipulate Lists/Array

Wayne Dickerson — Mon, 20 Aug 2018 07:55:17 GMT

Thanks Ingo,

I will have a look at that thread.

For anyone interested in the Second part and a method of placing polygons on alternating or different spacing for I have attached an example file I created to test out my facade options. (work in progress as always :))

Thanks

Wayne

communities.bentley.com/.../PolyEveryNthFloor.dgn

RE: Manipulate Lists/Array

Ingo — Mon, 20 Aug 2018 07:26:40 GMT

Hi Wayne,

I had a simple example some days ago concerning a 'correctly' labeled pointlist where Volker showed 'the right way'.

I think there you can get the solution for your first question.

Ingo

RE: Manipulate Lists/Array

Wayne Dickerson — Mon, 20 Aug 2018 06:56:12 GMT

Update:

I think I worked out the second part.

using the Sublist I could specify the range(count) and return the desired rows of points every Nth spacing

function (Point[][] pntarray, int dRow, int dSpan)
{
    Point returnlist = {};

    for (int i = 0; i < pntarray.Count; i += dRow)
    {
    returnlist.Add(pntarray.Sublist(i,dSpan));

    }

    return returnlist;
}

actually ended up as a simple function call.

let me know if you can see any improvements

Thanks

Wayne

RE: Manipulate Lists/Array

Wayne Dickerson — Mon, 20 Aug 2018 06:22:29 GMT

Hi Volker,

Thanks for the pointers. (insert joke here)

One thing I overlooked was that I managed to input a 0 value for dRow which puts it into an infinite loop.

So I add an “if” statement around the loop as a safeguard. I think this is the best way to do it.

if (dRow > 0 && dItem >0)

I have 2 questions:

The return list is a flat list rather than an array, so if wanted to use the point as for a Polygon ByPointGrid it will error.

Is there an easy way to output the results as an array rather than a list?

The second question is if I needed to select 2 or 3 rows of points ever N rows? How would I go about writing a script for this.

I first thought I would need to find i being the first row of points I needed then adding a variable for the number of rows I needed about this say 3. Then loop again and find the next i and so on.

I have attached a picture to try and explain. Using this we could alternate façade panels every 3 floors.

So far I have the following: (which is obviously wrong but starting somewhere :) )

function (Point[][] pntarray, int dRow, int dItem, int dSpan)

{

Point returnlist = {};

int j=0;

// I believe this int j=0 needs to be within the for loop as it needs to reset for each loop.

if (dRow > 0 && dItem >0)

{

    for (int i = 0; i < pntarray[i].Count; i += dRow+j)

    //while (j < dSpan) ??

        {

        for (int k =0; k < pntarray[i].Count; k += dItem)


        returnlist.Add(pntarray[i][k]);

        // j ++; ??

        }

}

return returnlist;

}

The other approach I had was to select each row separately and then combine them in a ToList expression

{point1[0],point1[1],point1[2]}.ToList()

And

{point1[2],point1[3],point1[4]}.ToList()

Etc

And then place combine these back into 1 list with another ToList() which works perfectly for what I need for the output but it feels very manual. I am sure there is a way to achieve this via a script.

Or alternatively I could have used:

{point1.Sublist(0,3),point1.Sublist(2,3)}.ToList()

Which is much more refined, and looking at it you could probably for statement with a increment of 2 and a variable for the count. Maybe this is the best approach for this.

Any tips would be appreciated

Thanks
Wayne

RE: Manipulate Lists/Array

Mueller — Tue, 14 Aug 2018 21:22:50 GMT

Hi Wayne,

For a one-dimensional list you could use the list method "MembersAt". If your list is food = {potato, egg, cucumber, broccoli, fish, steak}, then food.MembersAt({1,3,5}) is {potato, cucumber, fish}.

For multi-dimensional lists, you'd have to iterate through the nested lists; however, instead of recreating the items you want to select you could add them to a list of the type:

function (Point[][] pntarray, int dRow, int dItem)
{
    Point returnlist = {};
    for (int i = 0; i < pntarray.Count; i += dRow)
    {
        for (int j = 0; j < pntarray[i].Count; j += dItem)
        {
            returnlist.Add(pntarray[i][j]);
        }
    }
    return returnlist;
}

This function code would reside in a FunctionCall node (or could be a named Script Function created in and added to the Functions dialog).

Additional refinements could be to add startRow and startItem and change the loops to start at those values, respectively, i.e. for (int i = startRow; … .

HTH,

Volker