gum::learning::DBInitializerFromCSV Class Reference

The class for initializing DatabaseTable and RawDatabaseTable instances from CSV files. More...

#include <agrum/base/database/DBInitializerFromCSV.h>

Inheritance diagram for gum::learning::DBInitializerFromCSV:

Collaboration diagram for gum::learning::DBInitializerFromCSV:

Public Types
enum class	InputType : char { STRING , DBCELL }
	the enumeration indicating the type of the data the IDBInitializer expects as input data More...

Public Member Functions
Constructors / Destructors
	DBInitializerFromCSV (const std::string filename, bool fileContainsNames=true, const std::string delimiter=",", const char commentmarker='#', const char quoteMarker='"')
	default constructor
	DBInitializerFromCSV (const DBInitializerFromCSV &from)
	copy constructor
	DBInitializerFromCSV (DBInitializerFromCSV &&from)
	move constructor
virtual DBInitializerFromCSV *	clone () const
	virtual copy constructor
virtual	~DBInitializerFromCSV ()
	destructor
Operators
DBInitializerFromCSV &	operator= (const DBInitializerFromCSV &from)
	copy operator
DBInitializerFromCSV &	operator= (DBInitializerFromCSV &&from)
	move operator
Accessors / Modifiers
const std::vector< std::string > &	variableNames ()
	returns the names of the variables in the input dataset
template<class DATABASE>
void	fillDatabase (DATABASE &database, const bool retry_insertion=false)
	fills the rows of the database table
std::size_t	throwingColumn () const
	This method indicates which column filling raised an exception, if any, during the execution of fillDatabase.

Protected Member Functions
virtual std::vector< std::string >	variableNames_ () final
	returns the names of the variables
virtual const std::vector< std::string > &	currentStringRow_ () final
	returns the content of the current row using strings
virtual bool	nextRow_ () final
	indicates whether there is a next row to read (and point on it)
virtual const DBRow< DBCell > &	currentDBCellRow_ ()
	asks the child class for the content of the current row using dbcells

Detailed Description

The class for initializing DatabaseTable and RawDatabaseTable instances from CSV files.

In aGrUM, the usual way to create DatabaseTable instances used by learning algorithms is to use the 4-step process below:

1. Create an IDBInitializer instance (either a DBInitializerFromCSV or a DBInitializerFromSQL). This will enable to get the variables corresponding to the columns of the DatabaseTable.
2. Knowing these variables, create a DBTranslatorSet for encoding the lines of the CSV file or those of the SQL result into the appropriate values for the learning algorithms.
3. Create the DatabaseTable, passing it the DBTranslatorSet created in the preceding step. Use the IDBInitializer to provide the variables' names to the DatabaseTable.
4. Use the IDBInitializer to add the lines of the CSV file or those of the SQL result into the DatabaseTable.

The following codes show the details of this process:

// 1/ use the initializer to parse all the columns/rows of a CSV file
gum::learning::DBInitializerFromCSV initializer ( "asia.csv" );
const auto& var_names = initializer.variableNames ();
const std::size_t nb_vars = var_names.size ();
 
// we create as many translators as there are variables
gum::learning::DBTranslator4LabelizedVariable translator;
gum::learning::DBTranslatorSet translator_set;
for ( std::size_t i = 0; i < nb_vars; ++i )
  translator_set.insertTranslator ( translator, i );
 
// create a DatabaseTable with these translators. For the moment, the
// DatabaseTable will be empty, i.e., it will contain no row
gum::learning::DatabaseTable database ( translator_set );
database.setVariableNames( initializer.variableNames () );
 
// use the DBInitializerFromCSV to fill the rows:
initializer.fillDatabase ( database );
// now, the database contains all the content of the CSV file
 
 
// 2/ use an IDBInitializer to initialize a DatabaseTable, but ignore
// some columns.
gum::learning::DBInitializerFromCSV initializer2 ( "asia.csv" );
gum::learning::DatabaseTable database2; // empty database
 
// indicate which columns of the CSV file should be read
database2.insertTranslator ( translator, 1 );
database2.insertTranslator ( translator, 3 );
database2.insertTranslator ( translator, 4 );
 
// sets the names of the columns correctly
database2.setVariableNames( initializer2.variableNames () );
 
// fill the rows:
initializer2.fillDatabase ( database2 );
// now all the rows of the CSV file have been transferred into database2,
// but only columns 1, 3 and 4 of the CSV file have been kept.
 
 
// 3/ another possibility to initialize a DatabaseTable, ignoring
// some columns:
gum::learning::DBInitializerFromCSV initializer3 ( "asia.csv" );
gum::learning::DatabaseTable database3 ( translator_set );
// here, database3 is an empty database but it contains already
// translators for all the columns of the CSV file. We shall now remove
// the columns/translators that are not wanted anymore
database3.ignoreColumn ( 0 );
database3.ignoreColumn ( 2 );
database3.ignoreColumn ( 5 );
database3.ignoreColumn ( 6 );
database3.ignoreColumn ( 7 );
// asia contains 8 columns. The above ignoreColumns keep only columns
// 1, 3 and 4.
 
// sets the names of the columns correctly
database3.setVariableNames( initializer3.variableNames () );
// fill the rows:
initializer3.fillDatabase ( database3 );
// now all the rows of the CSV file have been transferred into database3,
// but only columns 1, 3 and 4 of the CSV file have been kept.

Definition at line 151 of file DBInitializerFromCSV.h.

Member Enumeration Documentation

InputType

enum class gum::learning::IDBInitializer::InputType : char

stronginherited

the enumeration indicating the type of the data the IDBInitializer expects as input data

Enumerator
STRING
DBCELL

Definition at line 139 of file IDBInitializer.h.

: char { STRING, DBCELL };

Constructor & Destructor Documentation

DBInitializerFromCSV() [1/3]

gum::learning::DBInitializerFromCSV::DBInitializerFromCSV	(	const std::string	filename,
		bool	fileContainsNames = true,
		const std::string	delimiter = ",",
		const char	commentmarker = '#',
		const char	quoteMarker = '"' )

default constructor

Parameters

filename	the name of the CSV file
fileContainsNames	a Boolean indicating whether the first line of the CSV file contains the names of the columns
delimiter	the character that acts as the column separator in the CSV file
commentmarker	the character that marks the beginning of a comment
quoteMarker	the character that is used to quote the sentences in the CSV file

Referenced by DBInitializerFromCSV(), DBInitializerFromCSV(), clone(), operator=(), and operator=().

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DBInitializerFromCSV() [2/3]

gum::learning::DBInitializerFromCSV::DBInitializerFromCSV

(

const DBInitializerFromCSV &

from

)

copy constructor

the new initializer points to the same file as from, but it reparses it from scratch.

References DBInitializerFromCSV().

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DBInitializerFromCSV() [3/3]

gum::learning::DBInitializerFromCSV::DBInitializerFromCSV

(

DBInitializerFromCSV &&

from

)

move constructor

References DBInitializerFromCSV().

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~DBInitializerFromCSV()

virtual gum::learning::DBInitializerFromCSV::~DBInitializerFromCSV ( )

virtual

destructor

Member Function Documentation

clone()

virtual DBInitializerFromCSV * gum::learning::DBInitializerFromCSV::clone ( ) const

virtual

virtual copy constructor

Implements gum::learning::IDBInitializer.

References DBInitializerFromCSV().

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currentDBCellRow_()

virtual const DBRow< DBCell > & gum::learning::IDBInitializer::currentDBCellRow_ ( )

protectedvirtualinherited

asks the child class for the content of the current row using dbcells

If the child class parses DBRows, this method should be overloaded

currentStringRow_()

virtual const std::vector< std::string > & gum::learning::DBInitializerFromCSV::currentStringRow_ ( )

finalprotectedvirtual

returns the content of the current row using strings

Reimplemented from gum::learning::IDBInitializer.

References currentStringRow_().

Referenced by currentStringRow_().

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fillDatabase()

template<class DATABASE>

void gum::learning::IDBInitializer::fillDatabase ( DATABASE & database, const bool retry_insertion = false )

inherited

fills the rows of the database table

This method may raise exceptions when trying to insert new rows into the database table. See Method insertRow() of the database table.

Referenced by gum::learning::IBNLearner::Database::Database(), gum::learning::IBNLearner::Database::Database(), gum::learning::readFile(), and gum::learning::IBNLearner::readFile_().

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nextRow_()

virtual bool gum::learning::DBInitializerFromCSV::nextRow_ ( )

finalprotectedvirtual

indicates whether there is a next row to read (and point on it)

Implements gum::learning::IDBInitializer.

References nextRow_().

Referenced by nextRow_().

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operator=() [1/2]

DBInitializerFromCSV & gum::learning::DBInitializerFromCSV::operator=

(

const DBInitializerFromCSV &

from

)

copy operator

the initializer points to the same file as from, but it reparses it from scratch.

References DBInitializerFromCSV().

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operator=() [2/2]

DBInitializerFromCSV & gum::learning::DBInitializerFromCSV::operator=

(

DBInitializerFromCSV &&

from

)

move operator

the initializer points to the same file as from, but it reparses it from scratch.

References DBInitializerFromCSV().

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throwingColumn()

std::size_t gum::learning::IDBInitializer::throwingColumn ( ) const

inherited

This method indicates which column filling raised an exception, if any, during the execution of fillDatabase.

variableNames()

const std::vector< std::string > & gum::learning::IDBInitializer::variableNames ( )

inherited

returns the names of the variables in the input dataset

Referenced by gum::learning::IBNLearner::Database::Database(), gum::learning::IBNLearner::Database::Database(), gum::learning::readFile(), and gum::learning::IBNLearner::readFile_().

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variableNames_()

virtual std::vector< std::string > gum::learning::DBInitializerFromCSV::variableNames_ ( )

finalprotectedvirtual

returns the names of the variables

Implements gum::learning::IDBInitializer.

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The documentation for this class was generated from the following file:

• agrum/base/database/DBInitializerFromCSV.h