Logo ROOT  
Reference Guide
Go to the documentation of this file.
4#include "ROOT/RDataFrame.hxx"
7#include <memory>
9namespace arrow {
10class Table;
13namespace ROOT {
14namespace Internal {
15namespace RDF {
16class TValueGetter;
17} // namespace RDF
18} // namespace Internal
20namespace RDF {
22class RArrowDS final : public RDataSource {
24 std::shared_ptr<arrow::Table> fTable;
25 std::vector<std::pair<ULong64_t, ULong64_t>> fEntryRanges;
26 std::vector<std::string> fColumnNames;
27 size_t fNSlots = 0U;
29 std::vector<std::pair<size_t, size_t>> fGetterIndex; // (columnId, visitorId)
30 std::vector<std::unique_ptr<ROOT::Internal::RDF::TValueGetter>> fValueGetters; // Visitors to be used to track and get entries. One per column.
31 std::vector<void *> GetColumnReadersImpl(std::string_view name, const std::type_info &type) override;
34 RArrowDS(std::shared_ptr<arrow::Table> table, std::vector<std::string> const &columns);
35 ~RArrowDS();
36 const std::vector<std::string> &GetColumnNames() const override;
37 std::vector<std::pair<ULong64_t, ULong64_t>> GetEntryRanges() override;
38 std::string GetTypeName(std::string_view colName) const override;
39 bool HasColumn(std::string_view colName) const override;
40 bool SetEntry(unsigned int slot, ULong64_t entry) override;
41 void InitSlot(unsigned int slot, ULong64_t firstEntry) override;
42 void SetNSlots(unsigned int nSlots) override;
43 void Initialise() override;
44 std::string GetLabel() override;
48/// \brief Factory method to create a Apache Arrow RDataFrame.
49/// \param[in] table an apache::arrow table to use as a source.
50RDataFrame MakeArrowDataFrame(std::shared_ptr<arrow::Table> table, std::vector<std::string> const &columns);
52} // namespace RDF
54} // namespace ROOT
unsigned long long ULong64_t
Definition: RtypesCore.h:70
char name[80]
Definition: TGX11.cxx:109
int type
Definition: TGX11.cxx:120
RDataFrame data source class to interface with Apache Arrow.
Definition: RArrowDS.hxx:22
bool HasColumn(std::string_view colName) const override
Checks if the dataset has a certain column.
Definition: RArrowDS.cxx:492
RArrowDS(std::shared_ptr< arrow::Table > table, std::vector< std::string > const &columns)
Constructor to create an Arrow RDataSource for RDataFrame.
Definition: RArrowDS.cxx:387
void Initialise() override
Convenience method called before starting an event-loop.
Definition: RArrowDS.cxx:588
std::string GetLabel() override
Return a string representation of the datasource type.
Definition: RArrowDS.cxx:594
void SetNSlots(unsigned int nSlots) override
Inform RDataSource of the number of processing slots (i.e.
Definition: RArrowDS.cxx:553
Definition: RArrowDS.cxx:459
const std::vector< std::string > & GetColumnNames() const override
Returns a reference to the collection of the dataset's column names.
Definition: RArrowDS.cxx:463
void InitSlot(unsigned int slot, ULong64_t firstEntry) override
Convenience method called at the start of the data processing associated to a slot.
Definition: RArrowDS.cxx:510
std::vector< std::pair< ULong64_t, ULong64_t > > GetEntryRanges() override
Return ranges of entries to distribute to tasks.
Definition: RArrowDS.cxx:468
std::shared_ptr< arrow::Table > fTable
Definition: RArrowDS.hxx:24
std::vector< std::pair< size_t, size_t > > fGetterIndex
Definition: RArrowDS.hxx:29
std::vector< std::unique_ptr< ROOT::Internal::RDF::TValueGetter > > fValueGetters
Definition: RArrowDS.hxx:30
std::vector< void * > GetColumnReadersImpl(std::string_view name, const std::type_info &type) override
This needs to return a pointer to the pointer each value getter will point to.
Definition: RArrowDS.cxx:569
std::vector< std::string > fColumnNames
Definition: RArrowDS.hxx:26
std::string GetTypeName(std::string_view colName) const override
Type of a column as a string, e.g.
Definition: RArrowDS.cxx:474
std::vector< std::pair< ULong64_t, ULong64_t > > fEntryRanges
Definition: RArrowDS.hxx:25
bool SetEntry(unsigned int slot, ULong64_t entry) override
Advance the "cursors" returned by GetColumnReaders to the selected entry for a particular slot.
Definition: RArrowDS.cxx:501
RDataSource defines an API that RDataFrame can use to read arbitrary data formats.
ROOT's RDataFrame offers a high level interface for analyses of data stored in TTrees,...
Definition: RDataFrame.hxx:42
basic_string_view< char > string_view
RDataFrame MakeArrowDataFrame(std::shared_ptr< arrow::Table > table, std::vector< std::string > const &columns)
Factory method to create a Apache Arrow RDataFrame.
Definition: RArrowDS.cxx:603
VSD Structures.
Definition: StringConv.hxx:21