library: libTree #include "TEventList.h"

# TEventList

class description - source file - inheritance tree (.pdf)

## class TEventList : public TNamed

| Inheritance Chart:
`TObject`
| <- | `TNamed`
| <- | `TEventList` |

        public:

                            TEventList()
                            TEventList(const char* name, const char* title = "", Int_t initsize = 0, Int_t delta = 0)
                            TEventList(const TEventList& list)
                    virtual ~TEventList()
               virtual void Add(const TEventList* list)
             static TClass* Class()
               virtual void Clear(Option_t* option = "")
             virtual Bool_t Contains(Long64_t entry)
               virtual void Enter(Long64_t entry)
                TDirectory* GetDirectory() const
           virtual Long64_t GetEntry(Int_t index) const
              virtual Int_t GetIndex(Long64_t entry) const
          virtual Long64_t* GetList() const
              virtual Int_t GetN() const
             virtual Bool_t GetReapplyCut() const
              virtual Int_t GetSize() const
               virtual void Intersect(const TEventList* list)
            virtual TClass* IsA() const
              virtual Int_t Merge(TCollection* list)
                TEventList& operator=(const TEventList& list)
               virtual void Print(Option_t* option = "") const
               virtual void Reset(Option_t* option = "")
               virtual void Resize(Int_t delta = 0)
               virtual void SetDelta(Int_t delta = 100)
               virtual void SetDirectory(TDirectory* dir)
               virtual void SetName(const char* name)
               virtual void SetReapplyCut(Bool_t apply = kFALSE)
               virtual void ShowMembers(TMemberInspector& insp, char* parent)
               virtual void Sort()
               virtual void Streamer(TBuffer& b)
                       void StreamerNVirtual(TBuffer& b)
               virtual void Subtract(const TEventList* list)

### Data Members

        protected:

                Int_t fN          Number of elements in the list
                Int_t fSize       Size of array
                Int_t fDelta      Increment size
               Bool_t fReapply    If true, TTree::Draw will 'reapply' the original cut
            Long64_t* fList       [fN]Array of elements
          TDirectory* fDirectory  ! Pointer to directory holding this tree

## Class Description

     A TEventList object is a list of selected events (entries) in a TTree

     A TEventList is automatically generated by TTree::Draw: example
          tree->Draw(">>elist1","x<0 && y> 0");
             In this example, a TEventList object named "elist1" will be
             generated. (Previous contents are overwritten).
          tree->Draw(">>+elist1","x<0 && y> 0");
             In this example, selected entries are added to the list.

     The TEventList object is added to the list of objects in the current
     directory.
     Use TTree:SetEventList(TEventList *list) to inform TTree that you
     want to use the list as input. The following code gets a pointer to
     the TEventList object created in the above commands:
         TEventList *list = (TEventList*)gDirectory->Get("elist1");

     Use function Enter to enter an element in the list
     The function Add may be used to merge two lists.
     The function Subtract may be used to subtract two lists.
     The function Reset may be used to reset a list.
     Use TEventList::Print(option) to print the contents.
          (option "all" prints all the list entries).
       Operators + and - correspond to functions Add and Subtract.
     A TEventList object can be saved on a file via the Write function.

TEventList(): TNamed()

    *-*-*-*-*-*Default constructor for a EventList*-*-*-*-*-*-*-*-*-*-*-*-*
    *-*        ==================================

TEventList(const char *name, const char *title, Int_t initsize, Int_t delta) :TNamed(name,title), fReapply(kFALSE)

    *-*-*-*-*-*-*-*-*-*-*-*-*Create a EventList*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
    *-*                      =================

      This Eventlist is added to the list of objects in current directory

TEventList(const TEventList &list) : TNamed(list)

    *-*-*-*-*-*-*-*-*-*-*-*-*Copy constructor*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
    *-*                      ================

~TEventList()

    *-*-*-*-*-*Default destructor for a EventList*-*-*-*-*-*-*-*-*-*-*-*
    *-*        =================================

void Add(const TEventList *alist)

              Merge contents of alist with this list.
       Both alist and this list are assumed to be sorted prior to this call

Bool_t Contains(Long64_t entry)

              Return TRUE if list contains entry.

void Enter(Long64_t entry)

              Enter element entry into the list

Long64_t GetEntry(Int_t index) const

           Return value of entry at index in the list.
           Return -1 if index is not in the list range

Int_t GetIndex(Long64_t entry) const

     Return index in the list of element with value entry
     array is supposed  to be sorted prior to this call.
     If match is found, function returns position of element.
     If no match found, function returns -1.

void Intersect(const TEventList *alist)

     Remove elements from this list that are NOT present in alist.

Int_t Merge(TCollection *list)

     Merge entries in all the TEventList in the collection in this event list

void Print(Option_t *option) const

              Print contents of this list

void Reset(Option_t *)

              Reset number of entries in event list

void Resize(Int_t delta)

              Resize list by delta entries

void SetDirectory(TDirectory *dir)

     Remove reference to this EventList from current directory and add
     reference to new directory dir. dir can be 0 in which case the list
     does not belong to any directory.

void SetName(const char *name)

     Change the name of this TEventList

void Sort()

              Sort list entries in increasing order

void Streamer(TBuffer &b)

     Stream an object of class TEventList.

void Subtract(const TEventList *alist)

     Remove elements from this list that are present in alist.

### Inline Functions

                   void Clear(Option_t* option = "")
            TDirectory* GetDirectory() const
              Long64_t* GetList() const
                  Int_t GetN() const
                 Bool_t GetReapplyCut() const
                  Int_t GetSize() const
                   void SetDelta(Int_t delta = 100)
                   void SetReapplyCut(Bool_t apply = kFALSE)
            TEventList& operator=(const TEventList& list)
                TClass* Class()
                TClass* IsA() const
                   void ShowMembers(TMemberInspector& insp, char* parent)
                   void StreamerNVirtual(TBuffer& b)

Author: Rene Brun 11/02/97
Last update: root/tree:$Name: $:$Id: TEventList.cxx,v 1.13 2005/06/03 07:37:06 brun Exp $
Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *