ROOT 6.08/07 Reference Guide |
TTreeReader is a simple, robust and fast interface to read values from a TTree, TChain or TNtuple.
It uses TTreeReaderValue<T> and TTreeReaderArray<T> to access the data.
Example code can be found in tutorials/tree/hsimpleReader.C and tutorials/trees/h1analysisTreeReader.h and tutorials/trees/h1analysisTreeReader.C for a TSelector.
Roottest contains an example showing the full power.
A simpler analysis example - the one from the tutorials - can be found below: it histograms a function of the px and py branches.
A more complete example including error handling and a few combinations of TTreeReaderValue and TTreeReaderArray would look like this:
Definition at line 48 of file TTreeReader.h.
Classes | |
class | Iterator_t |
Iterate through the entries of a TTree. More... | |
Public Types | |
enum | EEntryStatus { kEntryValid = 0, kEntryNotLoaded, kEntryNoTree, kEntryNotFound, kEntryChainSetupError, kEntryChainFileError, kEntryDictionaryError, kEntryLast } |
typedef Iterator_t | iterator |
Public Types inherited from TObject | |
enum | { kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff } |
enum | { kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) } |
enum | EStatusBits { kCanDelete = BIT(0), kMustCleanup = BIT(3), kObjInCanvas = BIT(3), kIsReferenced = BIT(4), kHasUUID = BIT(5), kCannotPick = BIT(6), kNoContextMenu = BIT(8), kInvalidObject = BIT(13) } |
Public Member Functions | |
TTreeReader () | |
TTreeReader (TTree *tree) | |
Access data from tree. More... | |
TTreeReader (const char *keyname, TDirectory *dir=NULL) | |
Access data from the tree called keyname in the directory (e.g. More... | |
~TTreeReader () | |
Tell all value readers that the tree reader does not exist anymore. More... | |
Iterator_t | begin () |
Return an iterator to the 0th TTree entry. More... | |
Iterator_t | end () const |
Long64_t | GetCurrentEntry () const |
Returns the index of the current entry being read. More... | |
Long64_t | GetEntries (Bool_t force) const |
EEntryStatus | GetEntryStatus () const |
TTree * | GetTree () const |
Bool_t | IsChain () const |
Bool_t | Next () |
void | Restart () |
Restart a Next() loop from the first entry. More... | |
void | SetChain (const char *, TFileCollection *) |
EEntryStatus | SetEntriesRange (Long64_t beginEntry, Long64_t endEntry) |
Set the range of entries to be processed. More... | |
EEntryStatus | SetEntry (Long64_t entry) |
void | SetLastEntry (Long64_t entry) |
EEntryStatus | SetLocalEntry (Long64_t entry) |
void | SetTree (TTree *tree) |
Set (or update) the which tree to reader from. More... | |
void | SetTree (const char *, TDirectory *) |
Public Member Functions inherited from TObject | |
TObject () | |
TObject constructor. More... | |
TObject (const TObject &object) | |
TObject copy ctor. More... | |
virtual | ~TObject () |
TObject destructor. More... | |
void | AbstractMethod (const char *method) const |
Use this method to implement an "abstract" method that you don't want to leave purely abstract. More... | |
virtual void | AppendPad (Option_t *option="") |
Append graphics object to current pad. More... | |
virtual void | Browse (TBrowser *b) |
Browse object. May be overridden for another default action. More... | |
virtual const char * | ClassName () const |
Returns name of class to which the object belongs. More... | |
virtual void | Clear (Option_t *="") |
virtual TObject * | Clone (const char *newname="") const |
Make a clone of an object using the Streamer facility. More... | |
virtual Int_t | Compare (const TObject *obj) const |
Compare abstract method. More... | |
virtual void | Copy (TObject &object) const |
Copy this to obj. More... | |
virtual void | Delete (Option_t *option="") |
Delete this object. More... | |
virtual Int_t | DistancetoPrimitive (Int_t px, Int_t py) |
Computes distance from point (px,py) to the object. More... | |
virtual void | Draw (Option_t *option="") |
Default Draw method for all objects. More... | |
virtual void | DrawClass () const |
Draw class inheritance tree of the class to which this object belongs. More... | |
virtual TObject * | DrawClone (Option_t *option="") const |
Draw a clone of this object in the current pad. More... | |
virtual void | Dump () const |
Dump contents of object on stdout. More... | |
virtual void | Error (const char *method, const char *msgfmt,...) const |
Issue error message. More... | |
virtual void | Execute (const char *method, const char *params, Int_t *error=0) |
Execute method on this object with the given parameter string, e.g. More... | |
virtual void | Execute (TMethod *method, TObjArray *params, Int_t *error=0) |
Execute method on this object with parameters stored in the TObjArray. More... | |
virtual void | ExecuteEvent (Int_t event, Int_t px, Int_t py) |
Execute action corresponding to an event at (px,py). More... | |
virtual void | Fatal (const char *method, const char *msgfmt,...) const |
Issue fatal error message. More... | |
virtual TObject * | FindObject (const char *name) const |
Must be redefined in derived classes. More... | |
virtual TObject * | FindObject (const TObject *obj) const |
Must be redefined in derived classes. More... | |
virtual Option_t * | GetDrawOption () const |
Get option used by the graphics system to draw this object. More... | |
virtual const char * | GetIconName () const |
Returns mime type name of object. More... | |
virtual const char * | GetName () const |
Returns name of object. More... | |
virtual char * | GetObjectInfo (Int_t px, Int_t py) const |
Returns string containing info about the object at position (px,py). More... | |
virtual Option_t * | GetOption () const |
virtual const char * | GetTitle () const |
Returns title of object. More... | |
virtual UInt_t | GetUniqueID () const |
Return the unique object id. More... | |
virtual Bool_t | HandleTimer (TTimer *timer) |
Execute action in response of a timer timing out. More... | |
virtual ULong_t | Hash () const |
Return hash value for this object. More... | |
virtual void | Info (const char *method, const char *msgfmt,...) const |
Issue info message. More... | |
virtual Bool_t | InheritsFrom (const char *classname) const |
Returns kTRUE if object inherits from class "classname". More... | |
virtual Bool_t | InheritsFrom (const TClass *cl) const |
Returns kTRUE if object inherits from TClass cl. More... | |
virtual void | Inspect () const |
Dump contents of this object in a graphics canvas. More... | |
void | InvertBit (UInt_t f) |
virtual Bool_t | IsEqual (const TObject *obj) const |
Default equal comparison (objects are equal if they have the same address in memory). More... | |
virtual Bool_t | IsFolder () const |
Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More... | |
Bool_t | IsOnHeap () const |
virtual Bool_t | IsSortable () const |
Bool_t | IsZombie () const |
virtual void | ls (Option_t *option="") const |
The ls function lists the contents of a class on stdout. More... | |
void | MayNotUse (const char *method) const |
Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More... | |
virtual Bool_t | Notify () |
This method must be overridden to handle object notification. More... | |
void | Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const |
Use this method to declare a method obsolete. More... | |
void | operator delete (void *ptr) |
Operator delete. More... | |
void | operator delete[] (void *ptr) |
Operator delete []. More... | |
void * | operator new (size_t sz) |
void * | operator new (size_t sz, void *vp) |
void * | operator new[] (size_t sz) |
void * | operator new[] (size_t sz, void *vp) |
TObject & | operator= (const TObject &rhs) |
TObject assignment operator. More... | |
virtual void | Paint (Option_t *option="") |
This method must be overridden if a class wants to paint itself. More... | |
virtual void | Pop () |
Pop on object drawn in a pad to the top of the display list. More... | |
virtual void | Print (Option_t *option="") const |
This method must be overridden when a class wants to print itself. More... | |
virtual Int_t | Read (const char *name) |
Read contents of object with specified name from the current directory. More... | |
virtual void | RecursiveRemove (TObject *obj) |
Recursively remove this object from a list. More... | |
void | ResetBit (UInt_t f) |
virtual void | SaveAs (const char *filename="", Option_t *option="") const |
Save this object in the file specified by filename. More... | |
virtual void | SavePrimitive (std::ostream &out, Option_t *option="") |
Save a primitive as a C++ statement(s) on output stream "out". More... | |
void | SetBit (UInt_t f, Bool_t set) |
Set or unset the user status bits as specified in f. More... | |
void | SetBit (UInt_t f) |
virtual void | SetDrawOption (Option_t *option="") |
Set drawing option for object. More... | |
virtual void | SetUniqueID (UInt_t uid) |
Set the unique object id. More... | |
virtual void | SysError (const char *method, const char *msgfmt,...) const |
Issue system error message. More... | |
Bool_t | TestBit (UInt_t f) const |
Int_t | TestBits (UInt_t f) const |
virtual void | UseCurrentStyle () |
Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More... | |
virtual void | Warning (const char *method, const char *msgfmt,...) const |
Issue warning message. More... | |
virtual Int_t | Write (const char *name=0, Int_t option=0, Int_t bufsize=0) |
Write this object to the current directory. More... | |
virtual Int_t | Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const |
Write this object to the current directory. More... | |
Protected Member Functions | |
void | DeregisterValueReader (ROOT::Internal::TTreeReaderValueBase *reader) |
Remove a value reader for this tree. More... | |
ROOT::Internal::TNamedBranchProxy * | FindProxy (const char *branchname) const |
TCollection * | GetProxies () |
void | Initialize () |
Initialization of the director. More... | |
Bool_t | RegisterValueReader (ROOT::Internal::TTreeReaderValueBase *reader) |
Add a value reader for this tree. More... | |
EEntryStatus | SetEntryBase (Long64_t entry, Bool_t local) |
Load an entry into the tree, return the status of the read. More... | |
Protected Member Functions inherited from TObject | |
virtual void | DoError (int level, const char *location, const char *fmt, va_list va) const |
Interface to ErrorHandler (protected). More... | |
void | MakeZombie () |
Private Types | |
enum | EPropertyBits { kBitIsChain = BIT(14) } |
Private Attributes | |
ROOT::Internal::TBranchProxyDirector * | fDirector |
proxying director, owned More... | |
TDirectory * | fDirectory |
directory (or current file for chains) More... | |
EEntryStatus | fEntryStatus |
status of most recent read request More... | |
Long64_t | fLastEntry |
The last entry to be processed. More... | |
Int_t | fMostRecentTreeNumber |
TTree::GetTreeNumber() of the most recent tree. More... | |
THashTable | fProxies |
attached ROOT::TNamedBranchProxies; owned More... | |
Bool_t | fProxiesSet |
True if the proxies have been set, false otherwise. More... | |
TTree * | fTree |
tree that's read More... | |
std::deque< ROOT::Internal::TTreeReaderValueBase * > | fValues |
readers that use our director More... | |
Friends | |
class | ROOT::Internal::TTreeReaderArrayBase |
class | ROOT::Internal::TTreeReaderValueBase |
Additional Inherited Members | |
Static Public Member Functions inherited from TObject | |
static Long_t | GetDtorOnly () |
Return destructor only flag. More... | |
static Bool_t | GetObjectStat () |
Get status of object stat flag. More... | |
static void | SetDtorOnly (void *obj) |
Set destructor only flag. More... | |
static void | SetObjectStat (Bool_t stat) |
Turn on/off tracking of objects in the TObjectTable. More... | |
#include <TTreeReader.h>
typedef Iterator_t TTreeReader::iterator |
Definition at line 127 of file TTreeReader.h.
Definition at line 129 of file TTreeReader.h.
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private |
Enumerator | |
---|---|
kBitIsChain | our tree is a chain |
Definition at line 200 of file TTreeReader.h.
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inline |
Definition at line 140 of file TTreeReader.h.
TTreeReader::TTreeReader | ( | TTree * | tree | ) |
Access data from tree.
Definition at line 167 of file TTreeReader.cxx.
TTreeReader::TTreeReader | ( | const char * | keyname, |
TDirectory * | dir = NULL |
||
) |
Access data from the tree called keyname in the directory (e.g.
TFile) dir, or the current directory if dir is NULL. If keyname cannot be found, or if it is not a TTree, IsZombie() will return true.
Definition at line 188 of file TTreeReader.cxx.
TTreeReader::~TTreeReader | ( | ) |
Tell all value readers that the tree reader does not exist anymore.
Definition at line 205 of file TTreeReader.cxx.
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inline |
Return an iterator to the 0th TTree entry.
Definition at line 182 of file TTreeReader.h.
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protected |
Remove a value reader for this tree.
Definition at line 406 of file TTreeReader.cxx.
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inline |
Definition at line 185 of file TTreeReader.h.
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inlineprotected |
Definition at line 189 of file TTreeReader.h.
Long64_t TTreeReader::GetCurrentEntry | ( | ) | const |
Returns the index of the current entry being read.
Definition at line 267 of file TTreeReader.cxx.
Definition at line 178 of file TTreeReader.h.
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inline |
Definition at line 175 of file TTreeReader.h.
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inlineprotected |
Definition at line 191 of file TTreeReader.h.
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inline |
Definition at line 177 of file TTreeReader.h.
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protected |
Initialization of the director.
Definition at line 218 of file TTreeReader.cxx.
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inline |
Definition at line 159 of file TTreeReader.h.
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inline |
Definition at line 161 of file TTreeReader.h.
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protected |
Add a value reader for this tree.
Definition at line 391 of file TTreeReader.cxx.
void TTreeReader::Restart | ( | ) |
Restart a Next() loop from the first entry.
Definition at line 258 of file TTreeReader.cxx.
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inline |
Definition at line 157 of file TTreeReader.h.
TTreeReader::EEntryStatus TTreeReader::SetEntriesRange | ( | Long64_t | beginEntry, |
Long64_t | endEntry | ||
) |
Set the range of entries to be processed.
This call is usually followed by an iteration of the range using TTreeReader::Next(), which will visit the the entries from begiNEntry
to endEntry - 1
. If endEntry > beginEntry, this call is equivalent to SetEntry(beginEntry - 1); SetLastEntry(endEntry);
. Otherwise endEntry
is ignored and only beginEntry
is set.
Definition at line 246 of file TTreeReader.cxx.
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inline |
Definition at line 162 of file TTreeReader.h.
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protected |
Load an entry into the tree, return the status of the read.
For chains, entry is the global (i.e. not tree-local) entry number, unless local
is true
, in which case entry
specifies the entry number within the current tree. This is needed for instance for TSelector::Process().
Definition at line 282 of file TTreeReader.cxx.
SetLastEntry() really sets the entry that Next()
will not read, i.e. the first entry number for which Next()
will return kFALSE. It is equivalant to end() for iterators. This interface has been deprecated in ROOT 6.10 and will be removed in ROOT 6.12. Please use SetEntriesRange() instead.
Definition at line 171 of file TTreeReader.h.
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inline |
Definition at line 163 of file TTreeReader.h.
Set (or update) the which tree to reader from.
tree can be a TTree or a TChain.
Definition at line 367 of file TTreeReader.cxx.
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inline |
Definition at line 156 of file TTreeReader.h.
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friend |
Definition at line 219 of file TTreeReader.h.
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friend |
Definition at line 218 of file TTreeReader.h.
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private |
proxying director, owned
Definition at line 208 of file TTreeReader.h.
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private |
directory (or current file for chains)
Definition at line 205 of file TTreeReader.h.
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private |
status of most recent read request
Definition at line 206 of file TTreeReader.h.
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private |
The last entry to be processed.
When set (i.e. >= 0), it provides a way to stop looping over the TTree when we reach a certain entry: Next() returns kEntryLast when GetCurrentEntry() reaches fLastEntry
Definition at line 215 of file TTreeReader.h.
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private |
TTree::GetTreeNumber() of the most recent tree.
Definition at line 207 of file TTreeReader.h.
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private |
attached ROOT::TNamedBranchProxies; owned
Definition at line 210 of file TTreeReader.h.
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private |
True if the proxies have been set, false otherwise.
Definition at line 216 of file TTreeReader.h.
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private |
tree that's read
Definition at line 204 of file TTreeReader.h.
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private |
readers that use our director
Definition at line 209 of file TTreeReader.h.