|
ROOT 6.10/00 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.
You can generate a skeleton of TTreeReaderValue<T> and TTreeReaderArray<T> declarations for all of a tree's branches using TTree::MakeSelector().
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 42 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, kEntryBeyondEnd } |
| 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 ()=default | |
| TTreeReader (TTree *tree, TEntryList *entryList=nullptr) | |
| Access data from tree. More... | |
| TTreeReader (const char *keyname, TDirectory *dir, TEntryList *entryList=nullptr) | |
| Access data from the tree called keyname in the directory (e.g. More... | |
| TTreeReader (const char *keyname, TEntryList *entryList=nullptr) | |
| ~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 |
| Return an iterator beyond the last TTree entry. More... | |
| Long64_t | GetCurrentEntry () const |
| Returns the index of the current entry being read. More... | |
| Long64_t | GetEntries (Bool_t force) const |
| Returns the number of entries of the TEntryList if one is provided, else of the TTree / TChain, independent of a range set by SetEntriesRange(). More... | |
| TEntryList * | GetEntryList () const |
| EEntryStatus | GetEntryStatus () const |
| TTree * | GetTree () const |
| Bool_t | IsChain () const |
| void | SetTree (TTree *tree, TEntryList *entryList=nullptr) |
| Set (or update) the which tree to read from. More... | |
| void | SetTree (const char *keyname, TEntryList *entryList=nullptr) |
| void | SetTree (const char *keyname, TDirectory *dir, TEntryList *entryList=nullptr) |
| Set (or update) the which tree to read from, passing the name of a tree in a directory. More... | |
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 selected pad for instance with: gROOT->SetSelectedPad(gPad). 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), kBitHaveWarnedAboutEntryListAttachedToTTree = BIT(15) } |
Private Attributes | |
| ROOT::Internal::TBranchProxyDirector * | fDirector = nullptr |
| proxying director, owned More... | |
| Long64_t | fEndEntry = -1 |
| The end of the entry loop. More... | |
| Long64_t | fEntry = -1 |
| Current (non-local) entry of fTree or of fEntryList if set. More... | |
| TEntryList * | fEntryList = nullptr |
| entry list to be used More... | |
| EEntryStatus | fEntryStatus = kEntryNotLoaded |
| status of most recent read request More... | |
| Int_t | fMostRecentTreeNumber = -1 |
| TTree::GetTreeNumber() of the most recent tree. More... | |
| THashTable | fProxies |
| attached ROOT::TNamedBranchProxies; owned More... | |
| Bool_t | fProxiesSet = kFALSE |
| True if the proxies have been set, false otherwise. More... | |
| TTree * | fTree = nullptr |
| 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 |
Entry setters | |
| void Misnomer and | duplication |
| Bool_t | Next () |
| Move to the next entry (or index of the TEntryList if that is set). More... | |
| EEntryStatus | SetEntry (Long64_t entry) |
| Set the next entry (or index of the TEntryList if that is set). More... | |
| EEntryStatus | SetLocalEntry (Long64_t entry) |
| Set the next local tree entry. More... | |
| void | SetLastEntry (Long64_t endEntry) R__DEPRECATED(6 |
| please use | SetEntriesRange ()!") |
| EEntryStatus | SetEntriesRange (Long64_t beginEntry, Long64_t endEntry) |
Set the range of entries to be loaded by Next(); end will not be loaded. More... | |
| void | Restart () |
| Restart a Next() loop from entry 0 (of TEntryList index 0 of fEntryList is set). More... | |
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 121 of file TTreeReader.h.
Definition at line 123 of file TTreeReader.h.
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private |
| Enumerator | |
|---|---|
| kBitIsChain |
our tree is a chain |
| kBitHaveWarnedAboutEntryListAttachedToTTree |
the tree had a TEntryList and we have warned about that |
Definition at line 230 of file TTreeReader.h.
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default |
| TTreeReader::TTreeReader | ( | TTree * | tree, |
| TEntryList * | entryList = nullptr |
||
| ) |
Access data from tree.
Definition at line 172 of file TTreeReader.cxx.
| TTreeReader::TTreeReader | ( | const char * | keyname, |
| TDirectory * | dir, | ||
| TEntryList * | entryList = nullptr |
||
| ) |
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.
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inline |
Definition at line 138 of file TTreeReader.h.
| TTreeReader::~TTreeReader | ( | ) |
Tell all value readers that the tree reader does not exist anymore.
Definition at line 199 of file TTreeReader.cxx.
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inline |
Return an iterator to the 0th TTree entry.
Definition at line 211 of file TTreeReader.h.
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protected |
Remove a value reader for this tree.
Definition at line 470 of file TTreeReader.cxx.
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inline |
Return an iterator beyond the last TTree entry.
Definition at line 215 of file TTreeReader.h.
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inlineprotected |
Definition at line 219 of file TTreeReader.h.
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inline |
Returns the index of the current entry being read.
If IsChain(), the returned index corresponds to the global entry number (i.e. not the entry number local to the chain's current tree). If fEntryList, the returned index corresponds to an index in the TEntryList; to translate to the TChain's / TTree's entry number pass it through reader.GetEntryList()->GetEntry(reader.GetCurrentEntry()).
Definition at line 208 of file TTreeReader.h.
Returns the number of entries of the TEntryList if one is provided, else of the TTree / TChain, independent of a range set by SetEntriesRange().
| force | If IsChain() and force, determines whether all TFiles of this TChain should be opened to determine the exact number of entries of the TChain. If !IsChain(), force is ignored. |
Definition at line 281 of file TTreeReader.cxx.
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inline |
Definition at line 152 of file TTreeReader.h.
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inline |
Definition at line 197 of file TTreeReader.h.
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inlineprotected |
Definition at line 221 of file TTreeReader.h.
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inline |
Definition at line 151 of file TTreeReader.h.
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protected |
Initialization of the director.
Definition at line 212 of file TTreeReader.cxx.
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inline |
Definition at line 149 of file TTreeReader.h.
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inline |
Move to the next entry (or index of the TEntryList if that is set).
while (reader.Next()) { ... } Definition at line 160 of file TTreeReader.h.
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protected |
Add a value reader for this tree.
Definition at line 455 of file TTreeReader.cxx.
| void TTreeReader::Restart | ( | ) |
Restart a Next() loop from entry 0 (of TEntryList index 0 of fEntryList is set).
Definition at line 266 of file TTreeReader.cxx.
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inline |
Definition at line 187 of file TTreeReader.h.
| TTreeReader::EEntryStatus TTreeReader::SetEntriesRange | ( | Long64_t | beginEntry, |
| Long64_t | endEntry | ||
| ) |
Set the range of entries to be loaded by Next(); end will not be loaded.
If end <= begin, end is ignored (set to -1) and only begin is used. Example:
| beginEntry | The first entry to be loaded by Next(). |
| endEntry | The entry where Next() will return kFALSE, not loading it. |
Definition at line 245 of file TTreeReader.cxx.
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inline |
Set the next entry (or index of the TEntryList if that is set).
| entry | If not TEntryList is set, the entry is a global entry (i.e. not the entry number local to the chain's current tree). |
entry's read status, i.e. whether the entry is available. Definition at line 169 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 299 of file TTreeReader.cxx.
Next() will stop iteration on. Equivalent to the preferred SetEntriesRange(0, end)| endEntry | The entry that Next() will return kFALSE on (i.e. not load anymore). |
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inline |
Set the next local tree entry.
If a TEntryList is set, this function is equivalent to SetEntry().
| entry | Entry number of the TChain's current TTree. This is the entry number passed for instance by TSelector::Process(entry), i.e. within TSelector::Process() always use SetLocalEntry() and not SetEntry()! |
entry's read status, i.e. whether the entry is available. Definition at line 179 of file TTreeReader.h.
| void TTreeReader::SetTree | ( | TTree * | tree, |
| TEntryList * | entryList = nullptr |
||
| ) |
Set (or update) the which tree to read from.
tree can be a TTree or a TChain.
Definition at line 411 of file TTreeReader.cxx.
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inline |
Definition at line 144 of file TTreeReader.h.
| void TTreeReader::SetTree | ( | const char * | keyname, |
| TDirectory * | dir, | ||
| TEntryList * | entryList = nullptr |
||
| ) |
Set (or update) the which tree to read from, passing the name of a tree in a directory.
| keyname | - name of the tree in dir |
| dir | - the TDirectory to load keyname from (or gDirectory if nullptr) |
| entryList | - the TEntryList to attach to the TTreeReader. |
Definition at line 443 of file TTreeReader.cxx.
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friend |
Definition at line 252 of file TTreeReader.h.
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friend |
Definition at line 251 of file TTreeReader.h.
| void Misnomer and TTreeReader::duplication |
Definition at line 187 of file TTreeReader.h.
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private |
proxying director, owned
Definition at line 239 of file TTreeReader.h.
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private |
The end of the entry loop.
When set (i.e. >= 0), it provides a way to stop looping over the TTree when we reach a certain entry: Next() returns kFALSE when GetCurrentEntry() reaches fEndEntry.
Definition at line 248 of file TTreeReader.h.
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private |
Current (non-local) entry of fTree or of fEntryList if set.
Definition at line 243 of file TTreeReader.h.
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private |
entry list to be used
Definition at line 236 of file TTreeReader.h.
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private |
status of most recent read request
Definition at line 237 of file TTreeReader.h.
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private |
TTree::GetTreeNumber() of the most recent tree.
Definition at line 238 of file TTreeReader.h.
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private |
attached ROOT::TNamedBranchProxies; owned
Definition at line 241 of file TTreeReader.h.
True if the proxies have been set, false otherwise.
Definition at line 249 of file TTreeReader.h.
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private |
tree that's read
Definition at line 235 of file TTreeReader.h.
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private |
readers that use our director
Definition at line 240 of file TTreeReader.h.