Cannot access bool array of an TTree in PyROOT

[yesw2000]

Hi,

I have a bool array in my TTree, and tried to access it in PyROOT, and it failed.

newTree.Print()

---

*Tree :newTree : a test TTree of bool variable/array *
*Entries : 2 : Total = 1871 bytes File Size = 658 *

•    :          : Tree compression factor =   1.00                       *
  

---

*Br 0 :boolVar : boolVar/O *
*Entries : 2 : Total Size= 727 bytes File Size = 79 *
*Baskets : 1 : Basket Size= 32000 bytes Compression= 1.00 *
…
*Br 1 :boolArray : boolArray[4]/O *
*Entries : 2 : Total Size= 759 bytes File Size = 87 *
*Baskets : 1 : Basket Size= 32000 bytes Compression= 1.00 *
…

newTree.Show(0)
======> EVENT:0
boolVar = 1
boolArray = 1,
1, 1, 1
print newTree.boolVar
1
print newTree.boolArray
140736287928792
print type(newTree.boolVar)
<type ‘int’>
print type(newTree.boolArray)
main:1: RuntimeWarning: creating converter for unknown type “Bool_t*”
<type ‘long’>

Is bool array supported in PyROOT? What is the proper way to access bool array of an TTree in pyROOT?

–Shuwei

[wlav]

Shuwei,

which version of ROOT are you using? Python does not support bool arrays, but in more recent versions of ROOT, there is a mapping of bool* through a char (i.e. byte) array, which works on most platforms.

Cheers,
Wim

[yesw2000]

Hi Wim,

The version I tried was ROOT-5.28.00g. I just tried 5.33.02 and bool array is supported in PyROOT of that version. Thanks.

–Shuwei