Hello Rooters,
I have a root file that contains two TTrees called raw_0;1 and raw_0;2. If I type raw_0;1->Scan() in cint, off course I get an error. If type raw_0->Print() I get the contents of the TTree ( I assume it’s the contents of the raw_0;2 i.e. the last cycle) which look like this
[code]******************************************************************************
*Tree :raw_0 : raw_0 *
*Entries : 89999999 : Total = 180284406 bytes File Size = 57151337 *
*Br 0 :signal_y : signal_y/S *
*Entries : 89999999 : Total Size= 180284076 bytes File Size = 57124673 *
*Baskets : 2956 : Basket Size= 3200000 bytes Compression= 3.15 *
…
[/code]
The problem is that I want to access both trees but I don’t know how to do it since I get puzzled about the “;” character.
Any idea on how to do it?
Thanks in advance!
Talk to the person who created these trees and ask to recreate them with two different names (e.g. “raw_0” and “raw_1”).
Well, that seems very difficult now…
So you’re implying that there is no way around it?
Regards
Usually, a new “cycle” contains all the data from all previous cycles. So, “;2” contains everything that “;1” has, plus additional new events (in other words, usually these are not two different trees).
Oh, I see…
This is very bad…
But in any case, how can I access both cycles?
If fir instance I make a histogram out of them I could subtract them to get them separately.
What do you get when you try: {
TFile *f = TFile::Open("your_file.root");
TTree *t;
t = (TTree*)f->Get("raw_0;1");
t->Print();
delete t;
t = (TTree*)f->Get("raw_0;2");
t->Print();
delete t;
t = (TTree*)f->Get("raw_0");
t->Print();
delete t;
}
TFile *f = TFile::Open("your_file.root");
TTree *t;
t = (TTree*)f->Get("raw_0;1");
t->Print();
I get
[code]******************************************************************************
*Tree :raw_0 : raw_0 *
*Entries : 46733808 : Total = 93749336 bytes File Size = 30027042 *
*Br 0 :signal_y : signal_y/S *
*Entries : 46733808 : Total Size= 93749006 bytes File Size = 30000378 *
*Baskets : 2928 : Basket Size= 3200000 bytes Compression= 3.12 *
…[/code]
While for the second tree
[code]******************************************************************************
*Tree :raw_0 : raw_0 *
*Entries : 89999999 : Total = 180284406 bytes File Size = 57151337 *
*Br 0 :signal_y : signal_y/S *
*Entries : 89999999 : Total Size= 180284076 bytes File Size = 57124673 *
*Baskets : 2956 : Basket Size= 3200000 bytes Compression= 3.15 *
…[/code]
Finally ignoring the cycles I get
[code]******************************************************************************
*Tree :raw_0 : raw_0 *
*Entries : 89999999 : Total = 180284406 bytes File Size = 57151337 *
*Br 0 :signal_y : signal_y/S *
*Entries : 89999999 : Total Size= 180284076 bytes File Size = 57124673 *
*Baskets : 2956 : Basket Size= 3200000 bytes Compression= 3.15 *
…[/code]
Try (note that “raw_0;2” contains about twice as many entries as “raw_0;1”, so it really suggests that this is the second “cycle” of the same tree): {
TFile *f = TFile::Open("your_file.root");
TTree *t1 = (TTree*)f->FindObjectAny("raw_0;1");
t1->Print();
TTree *t2 = (TTree*)f->FindObjectAny("raw_0;2");
t2->Print();
TCanvas *c = new TCanvas("c", "c");
c->Divide(1, 2);
c->cd(1); t1->Draw("signal_y");
c->cd(2); t2->Draw("signal_y");
c->cd(0);
}
t1->Print();
I get
[code]******************************************************************************
*Tree :raw_0 : raw_0 *
*Entries : 46733808 : Total = 93749336 bytes File Size = 30027042 *
*Br 0 :signal_y : signal_y/S *
*Entries : 46733808 : Total Size= 93749006 bytes File Size = 30000378 *
*Baskets : 2928 : Basket Size= 3200000 bytes Compression= 3.12 *
…
[/code]
t2->Print();
[code]******************************************************************************
*Tree :raw_0 : raw_0 *
*Entries : 89999999 : Total = 180284406 bytes File Size = 57151337 *
*Br 0 :signal_y : signal_y/S *
*Entries : 89999999 : Total Size= 180284076 bytes File Size = 57124673 *
*Baskets : 2956 : Basket Size= 3200000 bytes Compression= 3.15 *
…[/code]
And if I print in the canvas
Try: {
TFile *f = TFile::Open("your_file.root");
TTree *t1 = (TTree*)f->FindObjectAny("raw_0;1");
// t1->Print();
Long64_t t1_entries = t1->GetEntries();
TTree *t2 = (TTree*)f->FindObjectAny("raw_0;2");
// t2->Print();
Long64_t t2_entries = t2->GetEntries();
TCanvas *c = new TCanvas("c", "c");
c->Divide(2, 2);
c->cd(1);
t1->Draw("signal_y");
c->cd(2);
t2->Draw("signal_y");
c->cd(3);
t2->Draw("signal_y", "", "", t1_entries, 0);
c->cd(4);
t2->Draw("signal_y", "", "", (t2_entries - t1_entries), t1_entries);
c->cd(0);
}
So, everything is clear, isn’t it.
It seems that, in “t2”, entries from “0” to “t1_entries - 1” are the same as all entries in “t1”, and entries from “t1_entries” to “t2_entries - 1” are new (i.e. not contained in “t1”).
Yes, but how do you access them?
TTree::GetEntry -> "entry"
TTree::Project -> “firstentry” and "nentries"
TTree::Draw -> “firstentry” and “nentries” (see, for example, the macro from my previous post here how to do it)
