Hi Ray,
See TTree::Draw documentation in the following section:
// Special functions and variables
// ===============================
//
// Entry$: A TTree::Draw formula can use the special variable Entry$
// to access the entry number being read. For example to draw every
// other entry use:
// tree.Draw("myvar","Entry$%2==0");
//
// Entry$ : return the current entry number (== TTree::GetReadEntry())
// Entries$ : return the total number of entries (== TTree::GetEntries())
// Length$ : return the total number of element of this formula for this
// entry (==TTreeFormula::GetNdata())
// Iteration$: return the current iteration over this formula for this
// entry (i.e. varies from 0 to Length$).
Rene Brun
On
Fri, 14 Mar
2003, Ray Fliller III wrote:
>
>
> Hello Rooters.
>
> I have a TTree with a branch that contains an array. I would like to
> plot the values of the array vs. the index.
>
> for example, I have
>
> Float_t time;
> Float_t loss[10];
>
>
> TTree* foo=new TTree("foo","On You");
> foo->Branch("time",&time,"time/F");
> foo->Branch("loss",&loss,"loss[10]/F");
>
> //fill the tree
>
> In a perfect world I'd like to do
> foo->Draw("loss:i");
> and
> foo->Draw("loss:i:time");
>
> Can you help. I am using ROOT cvs from Monday.
>
>
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