I have a problem with TTree. I’m trying to read the data from file, when the data are only number all ok, but if 1 column is string I have a problem, not to read it but when I plot. Following the piece of code in pyroot:
tree= TTree ("tree","tree") #creeate TTree
tree.ReadFile(input_file,"source/C:HV:HV_err:R:R_err",'\t') # read data from file
gr = TGraphErrors(N,tree.GetV1(),tree.GetV2(),tree.GetV3(),tree.GetV4())
gr.Draw( 'AP' )
The output is always a plot with line but not with the data in the file (always the same line), why this?? (if I remove the string column work!)
Thanks in advance for your help!!
Would it be possible you send us a subset of your data file in order to run your example ?
Yes of course, this is an example: the first column is defined as source/C, and the other columns as default.
on 2008 1.5 31500000000 10000000000
off 2120.5 2.8 17300000000 6500000000
STBY 2115.09 2.45 19800000000 8900000000
on 2111.69 1.65 28800000000 2300000000
Thanks a lot!!
boog.dat (195 Bytes)
boog.C (498 Bytes)
TCanvas *canvas = new TCanvas("canvas","canvas");
TTree *tree = new TTree ("tree","tree");
Int_t N = tree->Draw("HV:R:HV_err:R_err","","goff");
Double_t *x = tree->GetVal(0);
Double_t *y = tree->GetVal(1);
Double_t *ex = tree->GetVal(2);
Double_t *ey = tree->GetVal(3);
TGraphErrors *gr = new TGraphErrors(N, x, y, ex, ey);
Yes now works!! It seems that the probelm was due to the “non declaration” columns… ??
Thanks a lot!!!
Yes because of the first /C all the following variables were considered as /C too