Getting a TGraph from contours

ROOT
1

Hi,

I need to get the Graph from a contour that has the highest number of elements. I know that with this

TObjArray *contours = gROOT->GetListOfSpecials()->FindObject(“contours”)
Int_t ncontours = contours->GetSize();
TList list = (TList)contours->At(i);
list->GetSize();

I can get the number of TGraphs, and then get the first one with

TGraph gr1 = (TGraph)list->First();

But I am counting the number of elements in each graph in a for loop (with GetN () )and in the end I need to get the graph with the highest number of elements. Would someone know how to do that?

2

Hi,

if you want to loop through a TList, here are all the options for doing so
root.cern.ch/doc/master/classTList.html

Then you just create two variables:

int highestCount(0); TGraph* graphWithHighestNumberOfElements;
And in the loop you do

int currentCount = (TGraph*)iter->GenN();
if (currentCount > highestCount) {
  highestCount = currentCount:
  graphWithHighestNumberOfElements =(TGraph*)(*iter);
}

You can do it shorter, but I made it verbose and lengthy as to make it easier to understand.

3

root.cern.ch/doc/master/ContourList_8C.html

4

[quote=“hegner”]Hi,

if you want to loop through a TList, here are all the options for doing so
root.cern.ch/doc/master/classTList.html

Then you just create two variables:

int highestCount(0); TGraph* graphWithHighestNumberOfElements;
And in the loop you do

int currentCount = (TGraph*)iter->GenN();
if (currentCount > highestCount) {
  highestCount = currentCount:
  graphWithHighestNumberOfElements =(TGraph*)(*iter);
}

You can do it shorter, but I made it verbose and lengthy as to make it easier to understand.[/quote]

Million thanks!