Why I use tree->Draw("branch") but got nothing?

Newbie
1

mode3->Print() //mode3 is a tree name in a root file

*Tree :mode3 : ks N-Tuple example *
*Entries : 0 : Total = 18194 bytes File Size = 1708 *

  •    :          : Tree compression factor =   1.00                       *

*Br 0 :deltaE_pkpi_3 : deltaE_pkpi_3/D *
*Entries : 0 : Total Size= 525 bytes One basket in memory *
*Baskets : 0 : Basket Size= 32000 bytes Compression= 1.00 *
…

mode3->Draw(“deltaE_pkpi_3”)

//then nothing comes out…
//What’s wrong here? In vscode I can see the branch in a histogram form.
//Also, if I write a histogram in a root file, I cannot draw the histogram at the same time, and if a draw a histogram from a root file instead of using TBrowser b, I got an empty canvas…
Thank you very much :wink:

2

Hi @Dyson ,

Your dataset is empty :point_up_2: . There is probably an issue with the program that writes it out.

Cheers,
Enrico