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 100 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 ()

std::unique_ptr< RNTupleReader >	Clone ()

void	EnableMetrics ()

RIterator	end ()

const RNTupleDescriptor &	GetDescriptor () const

NTupleSize_t	GetNEntries () const

template<typename T >
RNTupleView< T >	GetView (std::string_view fieldName)
	Provides access to an individual field that can contain either a scalar value or a collection, e.g. More...

RNTupleViewCollection	GetViewCollection (std::string_view fieldName)

RNTupleGlobalRange	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...

void	PrintInfo (const ENTupleInfo what=ENTupleInfo::kSummary, std::ostream &output=std::cout)
	Prints a detailed summary of the ntuple, including a list of fields. 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 Member Functions
void	ConnectModel ()

Private Attributes
Detail::RNTupleMetrics	fMetrics

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:

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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 58 of file RNTuple.cxx.

◆ RNTupleReader() [2/2]

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

explicit

The model is generated from the ntuple metadata on storage.

Definition at line 71 of file RNTuple.cxx.

◆ ~RNTupleReader()

ROOT::Experimental::RNTupleReader::~RNTupleReader ( )

Definition at line 83 of file RNTuple.cxx.

Member Function Documentation

◆ begin()

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

inline

Definition at line 170 of file RNTuple.hxx.

◆ Clone()

std::unique_ptr< RNTupleReader > ROOT::Experimental::RNTupleReader::Clone ( )

inline

Definition at line 136 of file RNTuple.hxx.

◆ ConnectModel()

void ROOT::Experimental::RNTupleReader::ConnectModel ( )

private

Definition at line 46 of file RNTuple.cxx.

◆ EnableMetrics()

void ROOT::Experimental::RNTupleReader::EnableMetrics ( )

inline

Definition at line 173 of file RNTuple.hxx.

◆ end()

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

inline

Definition at line 171 of file RNTuple.hxx.

◆ GetDescriptor()

const RNTupleDescriptor & ROOT::Experimental::RNTupleReader::GetDescriptor ( ) const

inline

Definition at line 140 of file RNTuple.hxx.

◆ GetNEntries()

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

inline

Definition at line 139 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 scalar 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 161 of file RNTuple.hxx.

◆ GetViewCollection()

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

inline

Definition at line 165 of file RNTuple.hxx.

◆ GetViewRange()

RNTupleGlobalRange ROOT::Experimental::RNTupleReader::GetViewRange ( )

inline

Definition at line 155 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 147 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 149 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 97 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 89 of file RNTuple.cxx.

◆ PrintInfo()

void ROOT::Experimental::RNTupleReader::PrintInfo	(	const ENTupleInfo	what = `ENTupleInfo::kSummary`,
		std::ostream &	output = `std::cout`
	)

Prints a detailed summary of the ntuple, including a list of fields.

Definition at line 104 of file RNTuple.cxx.

Member Data Documentation

◆ fMetrics

Detail::RNTupleMetrics ROOT::Experimental::RNTupleReader::fMetrics

private

Definition at line 103 of file RNTuple.hxx.

◆ fSource

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

private

Definition at line 102 of file RNTuple.hxx.

Libraries for ROOT::Experimental::RNTupleReader:

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Classes

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ RNTupleReader() [1/2]

◆ RNTupleReader() [2/2]

◆ ~RNTupleReader()

Member Function Documentation

◆ begin()

◆ Clone()

◆ ConnectModel()

◆ EnableMetrics()

◆ end()

◆ GetDescriptor()

◆ GetNEntries()

◆ GetView()

◆ GetViewCollection()

◆ GetViewRange()

◆ LoadEntry() [1/2]

◆ LoadEntry() [2/2]

◆ Open() [1/2]

◆ Open() [2/2]

◆ PrintInfo()

Member Data Documentation

◆ fMetrics

◆ fSource