[SOLVED] How to avoid null data?
lazarus / 55-TAChart

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madepabloh · 2014-08-18 19:00

I am writting a simple application what read a csv file, shows the
data into an stringgrid, and plot the values in a chart.

Since the numbers of columns is unknown, i add the series in runtime
by counting the humber of columns in the stringgrid. Everything works
fine except when the cells are empty.

I know there is an example in TAChart component about to assign "NaN"
to that component, and after explore the example and this forum, i
still can´t figure out how could i use this information to my case.

This is the procedure i create to read the stringgrid and create
lineseries in the Chart:
Code: [Select]procedure TMain.PlotData (Table: TstringGrid; Chart:
TChart);
 var
  colnumber: Integer;
  rownumber: integer;
  ls: Tlineseries;
  x: TDateTime;
  y: double;

begin
  Chart.ClearSeries;
  colnumber := Table.ColCount;
  rownumber := Table.RowCount;
  for i := 0 to colnumber-2 do
    begin
      ls := Tlineseries.Create(Chart);
      chart.addSeries(ls);
      ls.Legend.Format := Table.Cells[i+2, 1];
      for n := 2 to Rownumber-1 do
        begin
          x := StrToDateTime(Table.Cells[1, n]);
          y := StrToFloat(Table.Cells[i + 2, n]);
          ls.AddXY(x, y);
        end;
    end;
end;
How could i solve this issue? Thanks!

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taazz · 2014-08-18 19:29

Code: [Select]procedure TMain.PlotData (Table: TstringGrid; Chart:
TChart);
 var
  colnumber: Integer;
  rownumber: integer;
  ls: Tlineseries;
  x: TDateTime;
  y: double;

begin
  Chart.ClearSeries;
  colnumber := Table.ColCount;
  rownumber := Table.RowCount;
  for i := 0 to colnumber-2 do
    begin
      ls := Tlineseries.Create(Chart);
      chart.addSeries(ls);
      ls.Legend.Format := Table.Cells[i+2, 1];
      for n := 2 to Rownumber-1 do
        begin
          if TryStrToFloat(Table.Cells[i + 2, n], y) then begin
            x := StrToDateTime(Table.Cells[1, n]);
            ls.AddXY(x, y);
          end;
        end;
    end;
end;

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madepabloh · 2014-08-18 21:15

OMG! It was so simple!
I had on mind really complex procedures...

Thanks so much @taazz for to modify my code. It work nice now!
Thanks!!