Accessing sub entries in entries

Newbie
,
1

Hello, I am a beginner.

My branches are:

*Br 0 :event_number : Int_t *
*Entries : 10 : Total Size= 745 bytes One basket in memory *
*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 *
…
*Br 1 :momentum_unit : Int_t *
*Entries : 10 : Total Size= 739 bytes One basket in memory *
*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 *
…
*Br 2 :particles : Int_t particles_ *
*Entries : 10 : Total Size= 92400 bytes One basket in memory *
*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 *
…
*Br 3 :particles.pid : Int_t pid[particles_] *
*Entries : 10 : Total Size= 7711 bytes One basket in memory *
*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00
…
where Br 3 has 10 entries and each of those 10 entries have varying sub-entries when I used TBrowser to check individualevent_numberplots for example,tree->Draw(“particles.pid”, “event_number==1”), but i am not able to access the sub-entries and when I printparticles.pid` it only returns 24 subentries repeatedly for all 10 entries.

Any suggestions? Thank you!!!

My current C code is:

TFile f("TTreefile.root");
TTree* tree;
f.GetObject("tree", tree);
Int_t totalEntries = tree->GetEntries();
Int_t event_number, momentum_unit, pid[particles_];

tree->SetBranchAddress("event_number",&event_number);
tree->SetBranchAddress("particles", &particles_);
tree->SetBranchAddress("particles.pid", pid);


for (int i = 0; i < totalEntries; ++i) {
     tree->GetEntry(i);
      for (Int_t j=0; j< particles_; ++j){
         printf("Sub-entry %d: %d\n", i++, pid[i]);
      }

}

ROOT Version: 6.26/06
Platform: mac
Compiler: Not Provided

2

Welcome to the ROOT forum

Maybe you can provide your file TTreefile.root in order to inspect it ?

3

I am not able to attach or link the root file as I am a new user, is there is a way to share the root file?

Thank you!!

4

Dear @d_ana ,

Is this a good starting point for you?

ROOT::RDataFrame df{"tree", "TTreefile.root"};

df.Display()->Print();

Or equivalently in Python

df = ROOT.RDataFrame("tree", "TTreefile.root")
df.Display().Print()

For other operations you can define on your dataset, see the docs at ROOT: ROOT::RDataFrame Class Reference

Cheers,
Vincenzo

5

Thank you for the quick response. I am trying what you suggested, but is df.Display().Print() not supposed to print out anything?

6

Dear @d_ana ,

Not sure what you mean, Display does what the documentation suggests

$: rootls -l Run2012BC_DoubleMuParked_Muons.root
TTree  May 20 06:17 2019 Events;75 "Events" [current cycle]
TTree  May 20 06:17 2019 Events;74 "Events" [backup cycle]
$: python -c "import ROOT; df = ROOT.RDataFrame('Events','Run2012BC_DoubleMuParked_Muons.root'); df.Display().Print()"
+-----+-------------+------------+-----------+-------------+----------+-------+
| Row | Muon_charge | Muon_eta   | Muon_mass | Muon_phi    | Muon_pt  | nMuon | 
+-----+-------------+------------+-----------+-------------+----------+-------+
| 0   | -1          | 1.06683f   | 0.105658f | -0.0342727f | 10.7637f | 2     | 
|     | -1          | -0.563787f | 0.105658f | 2.54262f    | 15.7365f |       | 
+-----+-------------+------------+-----------+-------------+----------+-------+
| 1   | 1           | -0.427780f | 0.105658f | -0.274792f  | 10.5385f | 2     | 
|     | -1          | 0.349225f  | 0.105658f | 2.53978f    | 16.3271f |       | 
+-----+-------------+------------+-----------+-------------+----------+-------+
| 2   | 1           | 2.21086f   | 0.105658f | -1.22341f   | 3.27533f | 1     | 
+-----+-------------+------------+-----------+-------------+----------+-------+
| 3   | 1           | -1.58824f  | 0.105658f | -2.07730f   | 11.4292f | 4     | 
|     | 1           | -1.75118f  | 0.105658f | 0.251358f   | 17.6340f |       | 
|     | 1           | -1.59100f  | 0.105658f | -2.01305f   | 9.62473f |       | 
|     | 1           | -1.65596f  | 0.105658f | -1.84997f   | 3.50223f |       | 
+-----+-------------+------------+-----------+-------------+----------+-------+
| 4   | -1          | -2.17248f  | 0.105658f | -2.37001f   | 3.28344f | 4     | 
|     | -1          | -2.18253f  | 0.105658f | -2.30514f   | 3.64401f |       | 
|     | 1           | -1.12336f  | 0.105658f | -0.975242f  | 32.9112f |       | 
|     | 1           | -1.16290f  | 0.105658f | -0.773005f  | 23.7218f |       | 
+-----+-------------+------------+-----------+-------------+----------+-------+
7

Thank you @vpadulan, I think using RDataFrame is the right direction to explore.

One follow-up question: Is there a docs reference to save df.Display().Print()? Or something that would expand the entries ... e.g.:

+-----+----------------+
| Row | particles.mass | 
+-----+----------------+
| 5   | 0.93827000     | 
|     | 0.93827000     | 
|     | 0.0000000      | 
|     | 0.0000000      | 
|     | 1.5000000      | 
|     | 1.5000000      | 
|     | 0.0000000      | 
|     | 0.0000000      | 
|     | 0.0000000      | 
|     | 0.0000000      | 
|     | ...            | 
+-----+----------------+
``
8

HI @d_ana ,

Sure, it’s all in the docs ROOT: ROOT::RDF::RInterface< Proxied, DataSource > Class Template Reference .

nMaxCollectionElements Maximum number of collection elements to display per row.

9

Thank you @vpadulan for all your help!