Hi Alberto, On Fri, 26 Oct 2001, Alberto Pulvirenti wrote: > Hi everybody, > > I have some questions about the TTree and collection classes: > > 1) is it possible to CHANGE the value of a leaf in a selected entry of a > TTree? If so, how it should be done? > If you mean, replacing a leaf value in the Tree in the file, the answer is NO. This has been discussed many times in this list. > 2) when using a TTree::Draw() method with a condition, I was unable to > return to the initial "unconditioned" list of entries... is there > something to do, to reset the TTree and its entry variables (the ones I > get wit TTree::GetV1() & similar) I do not understand this point. Provide a short example that we can reproduce. > > 3) When using the TObjArray::Remove() or RemoveAt(), does it also delete > the object i want to remove? If not, is there another method which does > this? TObjArray::Remove does not delete the object. It only removes a reference to the object from the list. However, Remove returns a pointer to the object being removed. So, if you want to remove it from the list and also delete it, do: delete myarray->Remove(object); > > 4) What difference of utilization scopes is there between TObjArray, > TList and THashList? And which are, the latter's particular characteristics? See chapter on collection classes in the Users Guide > > 5) using an "aliroot" session (for who knows it) I wasn't able to clean > the RAM when clearing the TObjArrays I used... I must say that, in my > class, they are declared as stack data-member (not pointers). Should I > declare them in a different way? Again, not enough information to come with a diagnostic Rene Brun > > Thanks.... > > Alberto > > >
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