Dear experts , i have simple python script where i do :

```
import ROOT as r
from ROOT import RDataFrame as RDF
import numpy as np
df = RDF("toyTracks","ALLMERGED_fullP.root")
df_process = df.AsNumpy(columns=["txO", "tyO", "p","qop" ,"nHits","x_SciFis","y_SciFis" , "z_SciFis"])
```

When i look to the TFile content and i Show() branches i have

```
root [1] toyTracks->Show(1)
======> EVENT:1
eta = 1.6
phi = -3.14159
pt = 1058.12
txO = -0.420952
tyO = -5.15517e-17
p = 2727.27
qop = 0.000366667
mass = 493.68
nHits = 12
x_SciFis = -2101.21,
-2101.47, -2101.6, -2101.61, -2099.06, -2098.36,
-2097.59, -2096.75, -2089.67, -2088.46, -2087.21,
-2085.93
y_SciFis = 0.554104,
0.56029, 0.566658, 0.573208, 0.622267, 0.630302,
0.638538, 0.646973, 0.70872, 0.718357, 0.728107,
0.737964
z_SciFis = 7826,
7896, 7966, 8036, 8508, 8578,
8648, 8718, 9193, 9263, 9333,
9403
tx_SciFis = -0.0047049,
-0.00281031, -0.00102809, 0.000646468, 0.00952067, 0.0105347,
0.011484, 0.0123734, 0.0170837, 0.017614, 0.0181096,
0.0185732
ty_SciFis = 8.70786e-05,
8.96707e-05, 9.22753e-05, 9.48698e-05, 0.000113353, 0.000116228,
0.000119085, 0.000121901, 0.000136828, 0.000138495, 0.000140063,
0.000141537
```

and

```
*............................................................................*
*Br 8 :nHits : nHits/I *
*Entries : 3842054 : Total Size= 15380165 bytes File Size = 88173 *
*Baskets : 120 : Basket Size= 605184 bytes Compression= 174.40 *
*............................................................................*
*Br 9 :xSciFi : x_SciFis[nHits]/F *
*Entries : 3842054 : Total Size= 199926290 bytes File Size = 87312718 *
*Baskets : 1312 : Basket Size= 25600000 bytes Compression= 2.29 *
*............................................................................*
*Br 10 :ySciFi : y_SciFis[nHits]/F *
*Entries : 3842054 : Total Size= 199926290 bytes File Size = 79835379 *
*Baskets : 1312 : Basket Size= 25600000 bytes Compression= 2.50 *
*............................................................................*
*Br 11 :zSciFi : z_SciFis[nHits]/F *
*Entries : 3842054 : Total Size= 199926290 bytes File Size = 6827258 *
*Baskets : 1312 : Basket Size= 25600000 bytes Compression= 29.28 *
*............................................................................*
*Br 12 :txSciFi : tx_SciFis[nHits]/F *
*Entries : 3842054 : Total Size= 199927606 bytes File Size = 87489485 *
*Baskets : 1312 : Basket Size= 25600000 bytes Compression= 2.28 *
*............................................................................*
*Br 13 :tySciFi : ty_SciFis[nHits]/F *
*Entries : 3842054 : Total Size= 199927606 bytes File Size = 74680435 *
*Baskets : 1312 : Basket Size= 25600000 bytes Compression= 2.68 *
*............................................................................*
```

I generated thosee tuples using the suggested approach in

https://root.cern.ch/how/how-write-ttree-python

Thanks for any advice.

Renato

ROOT Version: 6.18/04

Built for macosx64 on Sep 26 2019, 09:45:39

From tags/v6-18-04@v6-18-04