ROOT::Experimental::RNTupleReader Class Reference

An RNTuple that is used to read data from storage.

An input ntuple provides data from storage as C++ objects. The ntuple model can be created from the data on storage or it can be imposed by the user. The latter case allows users to read into a specialized ntuple model that covers only a subset of the fields in the ntuple. The ntuple model is used when reading complete entries. Individual fields can be read as well by instantiating a tree view.

Definition at line 94 of file RNTuple.hxx.

Classes
class	RIterator

Public Member Functions
	RNTupleReader (std::unique_ptr< Detail::RPageSource > source)
	The model is generated from the ntuple metadata on storage. More...
	RNTupleReader (std::unique_ptr< RNTupleModel > model, std::unique_ptr< Detail::RPageSource > source)
	The user imposes an ntuple model, which must be compatible with the model found in the data on storage. More...
	~RNTupleReader ()
RIterator	begin ()
RIterator	end ()
std::string	GetInfo (const ENTupleInfo what=ENTupleInfo::kSummary)
NTupleSize_t	GetNEntries ()
template<typename T >
RNTupleView< T >	GetView (std::string_view fieldName)
	Provides access to an individual field that can contain either a skalar value or a collection, e.g. More...
RNTupleViewCollection	GetViewCollection (std::string_view fieldName)
RNTupleViewRange	GetViewRange ()
void	LoadEntry (NTupleSize_t index)
	Analogous to Fill(), fills the default entry of the model. More...
void	LoadEntry (NTupleSize_t index, REntry *entry)
	Fills a user provided entry after checking that the entry has been instantiated from the ntuple model. More...
Public Member Functions inherited from ROOT::Experimental::Detail::RNTuple
	RNTuple (const RNTuple &)=delete
	~RNTuple ()
RNTupleModel *	GetModel ()
RNTuple &	operator= (const RNTuple &)=delete

Static Public Member Functions
static std::unique_ptr< RNTupleReader >	Open (std::string_view ntupleName, std::string_view storage)
static std::unique_ptr< RNTupleReader >	Open (std::unique_ptr< RNTupleModel > model, std::string_view ntupleName, std::string_view storage)

Private Attributes
std::unique_ptr< Detail::RPageSource >	fSource

Additional Inherited Members
Protected Member Functions inherited from ROOT::Experimental::Detail::RNTuple
	RNTuple (std::unique_ptr< RNTupleModel > model)
	Only the derived RNTupleReader and RNTupleWriter can be instantiated. More...
Protected Attributes inherited from ROOT::Experimental::Detail::RNTuple
std::unique_ptr< RNTupleModel >	fModel
NTupleSize_t	fNEntries
	The number of entries is constant for reading and reflects the sum of Fill() operations when writing. More...

#include <ROOT/RNTuple.hxx>

Inheritance diagram for ROOT::Experimental::RNTupleReader:

Constructor & Destructor Documentation

RNTupleReader() [1/2]

ROOT::Experimental::RNTupleReader::RNTupleReader	(	std::unique_ptr< RNTupleModel >	model,
		std::unique_ptr< Detail::RPageSource >	source
	)

The user imposes an ntuple model, which must be compatible with the model found in the data on storage.

Definition at line 39 of file RNTuple.cxx.

RNTupleReader() [2/2]

ROOT::Experimental::RNTupleReader::RNTupleReader

(

std::unique_ptr< Detail::RPageSource >

source

)

The model is generated from the ntuple metadata on storage.

Definition at line 52 of file RNTuple.cxx.

~RNTupleReader()

ROOT::Experimental::RNTupleReader::~RNTupleReader

(

)

Definition at line 64 of file RNTuple.cxx.

Member Function Documentation

begin()

RIterator ROOT::Experimental::RNTupleReader::begin ( )

inline

Definition at line 154 of file RNTuple.hxx.

end()

RIterator ROOT::Experimental::RNTupleReader::end ( )

inline

Definition at line 155 of file RNTuple.hxx.

GetInfo()

std::string ROOT::Experimental::RNTupleReader::GetInfo

(

const ENTupleInfo

what = ENTupleInfo::kSummary

)

Definition at line 85 of file RNTuple.cxx.

GetNEntries()

NTupleSize_t ROOT::Experimental::RNTupleReader::GetNEntries ( )

inline

Definition at line 129 of file RNTuple.hxx.

GetView()

template<typename T >

RNTupleView< T > ROOT::Experimental::RNTupleReader::GetView ( std::string_view  fieldName )

inline

Provides access to an individual field that can contain either a skalar value or a collection, e.g.

GetView<double>("particles.pt") or GetView<std::vector<double>>("particle"). It can as well be the index field of a collection itself, like GetView<NTupleSize_t>("particle")

Definition at line 149 of file RNTuple.hxx.

GetViewCollection()

RNTupleViewCollection ROOT::Experimental::RNTupleReader::GetViewCollection ( std::string_view  fieldName )

inline

Definition at line 150 of file RNTuple.hxx.

GetViewRange()

RNTupleViewRange ROOT::Experimental::RNTupleReader::GetViewRange ( )

inline

Definition at line 143 of file RNTuple.hxx.

LoadEntry() [1/2]

void ROOT::Experimental::RNTupleReader::LoadEntry ( NTupleSize_t  index )

inline

Analogous to Fill(), fills the default entry of the model.

Returns false at the end of the ntuple. On I/O errors, raises an expection.

Definition at line 135 of file RNTuple.hxx.

LoadEntry() [2/2]

void ROOT::Experimental::RNTupleReader::LoadEntry ( NTupleSize_t  index, REntry *  entry  )

inline

Fills a user provided entry after checking that the entry has been instantiated from the ntuple model.

Definition at line 137 of file RNTuple.hxx.

Open() [1/2]

std::unique_ptr< ROOT::Experimental::RNTupleReader > ROOT::Experimental::RNTupleReader::Open ( std::string_view  ntupleName, std::string_view  storage  )

static

Definition at line 78 of file RNTuple.cxx.

Open() [2/2]

std::unique_ptr< ROOT::Experimental::RNTupleReader > ROOT::Experimental::RNTupleReader::Open ( std::unique_ptr< RNTupleModel >  model, std::string_view  ntupleName, std::string_view  storage  )

static

Definition at line 68 of file RNTuple.cxx.

Member Data Documentation

fSource

std::unique_ptr<Detail::RPageSource> ROOT::Experimental::RNTupleReader::fSource

private

Definition at line 96 of file RNTuple.hxx.

Libraries for ROOT::Experimental::RNTupleReader:

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