Hi Rene, hmm, no i don't think this was quite what i wanted (or i have not sufficiently understood it. In short what i have is a 2-D array (converted from hbook->root) stored in 1 leaf ie for each phioffset[i] (i=1->100) there are 1000 entries.. i need to be able to return any given entry for a given phioffset[i]. ((if i do t->Draw("phioffset[3]"); then i get a 1-D histo with 1000 entries)) the code : TLeaf *l_phioffset = t->GetLeaf(("phioffset"); l_phioffset->GetBranch()->GetEntry(5); //to read entry 5 double phioffset = l_phioffset->GetValue(); works fine for a 1-D array but in fact i need to be able to define an index of phioffset before i loop over its entries. If this was what you sent in your last email then perhaps you could clarify exactly how i should input the code as i don't seem to be able to run it without errors,.. many thanks for your ongoing support, Dan. CMS-Bristol http://cern.ch/dan.holmes On Thu, 28 Nov 2002, Rene Brun wrote: > Hi Dan, > > You can do > double phioffset3 = l_phioffset->GetValue(3); > or > double *phioffset = (double*)l_phioffset->GetValuepointer(); > and then access pihioffset[3]; > > Rene Brun > > On Thu, 28 Nov 2002, Daniel Holmes wrote: > > > thanks Rene, > > > > How do i change the code below so i can read a 2-D, array.. i can plot : > > t->Draw("phioffset[3]"); using the "phioffset" leaf. > > > > cheers, > > > > Dan. > > > > > > > With your example, you can do > > > TLeaf *l_phioffset = t->GetLeaf(("phioffset"); > > > l_phioffset->GetBranch()->GetEntry(5); //to read entry 5 > > > double phioffset = l_phioffset->GetValue(); > > > > > > Rene Brun > > > > > > > > >
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