Understand GetReapplyCut and SetReapplyCut of TEntryList

Hello,
I am trying to understand what the GetReapplyCut and SetReapplyCut of TEntryList are designed for? If can I apply additional cut on an existing entry list?

Thanks,
Zhiyi.

Hi,

The details are at root.cern.ch/root/html/TTree.html#TTree:Draw and read:[quote] If arrays are used in the selection critera, the entry entered in the
list are all the entries that have at least one element of the array that
satisfy the selection.
Example:
tree.Draw(">>pyplus",“fTracks.fPy>0”);
tree->SetEventList(pyplus);
tree->Draw(“fTracks.fPy”);
will draw the fPy of ALL tracks in event with at least one track with
a positive fPy.

To select only the elements that did match the original selection
use TEventList::SetReapplyCut or TEntryList::SetReapplyCut.
Example:
tree.Draw(">>pyplus",“fTracks.fPy>0”);
pyplus->SetReapplyCut(kTRUE);
tree->SetEventList(pyplus);
tree->Draw(“fTracks.fPy”);
will draw the fPy of only the tracks that have a positive fPy.[/quote]

[quote] If can I apply additional cut on an existing entry list?[/quote]The typical way to do so, is to call SetEventList and then to call Draw with the additional selections. However you might also be able to manipulate the “title” of the EntryList object …

Cheers,
Philippe.