gum::learning::DBCell Class Reference

The class representing the original values of the cells of databases. More...

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

Public Types
enum class	EltType : unsigned char { REAL , INTEGER , STRING , MISSING }
	the set of types possibly taken by the last element read More...

Public Member Functions
Constructors / Destructors
	DBCell ()
	default constructor (ontains a missing value)
	DBCell (const float nb)
	constructor for a real number
	DBCell (const int nb)
	constructor for an integer number
	DBCell (const std::string &str)
	constructor for a string
	DBCell (const DBCell &from)
	copy constructor
	DBCell (DBCell &&from)
	move constructor
	~DBCell ()
	destructor
Operators
DBCell &	operator= (const DBCell &from)
	copy operator
DBCell &	operator= (DBCell &&from)
	move operator
DBCell &	operator= (const float x)
	assignment operator
DBCell &	operator= (const int x)
	assignment operator
DBCell &	operator= (const std::string &x)
	assignment operator
bool	operator== (const DBCell &from) const
	test of equality
Accessors / Modifiers
EltType	type () const noexcept
	returns the current type of the DBCell
bool	convertType (const EltType newtype)
	try to convert the content of the DBCell into another type
float	real () const
	returns the DBcell as a real number
void	setReal (const float x)
	sets the content of the DBCell
void	setReal (std::string_view elt)
	sets the content of the DBCell from a string
int	integer () const
	returns the DBcell as an integer
void	setInteger (const int x)
	sets the content of the DBCell
void	setInteger (std::string_view elt)
	sets the content of the DBCell from a string
const std::string &	string () const
	returns the DBcell as a string
int	stringIndex () const
	returns the DBcell as the index of a string in a static bijection
void	setString (const std::string &elt)
	sets the content of the DBCell
void	setMissingState ()
	sets the DBCell as a missing element
bool	isMissing () const
	indicates whether the cell contains a missing value

Public Static Accessors / Modifiers
std::string	toString (const std::vector< std::string > &missingVals) const
	returns the content of the DBCell as a string, whatever its type
static const std::string &	string (const int index)
	strings are stored into a static bijection. Get its ith string
static EltType	bestType (std::string_view str, const std::vector< std::string > &missingVals)
	returns the best type to store a given element encoded as a string
static DBCell	bestDBCell (std::string_view str, const std::vector< std::string > &missingVals)
	returns the DBCell with the best type for an element encoded as a string
static bool	isInteger (std::string_view str)
	determines whether a string corresponds precisely to an integer
static bool	isReal (std::string_view str)
	determine whether a string corresponds precisely to a real number
static bool	isMissing (std::string_view str, const std::vector< std::string > &missingVals)
	checks whether a string correspond to a missing value

Detailed Description

The class representing the original values of the cells of databases.

Learning algorithms read input data, the so-called datasets, and infer their models. To be fast, they should not parse directly the original datasets, which are often databases of strings, but rather they should parse preprocessed data with types more suited for fast analysis. To do so, in aGrUM, learning algorithms parse datasets of DBTranslatedValue instances. However, sometimes, these algorithms make some decisions which, afterwards, they may realize were not so good and should be modified. For instance, when coping with continuous variables, they may use a discretization for fast learning the structure of a hybrid Bayesian network. But, given the structure found, they may try to find a better discretization. With a new discretization, the original dataset should be parsed again and mapped into new DBTranslatedValue instances. Unfortunately, reparsing, say, a CSV file or a SQL database, is time consuming. Sometimes, it is faster to read such datasets once and store them in an appropriate form that can be mapped easily into DBTranslatedValue instances. The RawDatabaseTable class is made precisely for this purpose and can be thought of as a 2-dimensional table, the elements of which are DBCell instances. The latter can actually encode compactly integers, real numbers, strings and even missing values. So they are very well suited to be the type of the cells of the RawDatabaseTable class.

Definition at line 94 of file DBCell.h.

Member Enumeration Documentation

EltType

enum class gum::learning::DBCell::EltType : unsigned char

strong

the set of types possibly taken by the last element read

Enumerator
REAL
INTEGER
STRING
MISSING

Definition at line 97 of file DBCell.h.

: unsigned char { REAL, INTEGER, STRING, MISSING };

Constructor & Destructor Documentation

DBCell() [1/6]

gum::learning::DBCell::DBCell

(

)

default constructor (ontains a missing value)

Referenced by DBCell(), DBCell(), bestDBCell(), operator=(), operator=(), operator=(), operator=(), operator=(), and operator==().

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DBCell() [2/6]

gum::learning::DBCell::DBCell

(

const float

nb

)

constructor for a real number

DBCell() [3/6]

gum::learning::DBCell::DBCell

(

const int

nb

)

constructor for an integer number

DBCell() [4/6]

gum::learning::DBCell::DBCell

(

const std::string &

str

)

constructor for a string

DBCell() [5/6]

gum::learning::DBCell::DBCell

(

const DBCell &

from

)

copy constructor

References DBCell().

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DBCell() [6/6]

gum::learning::DBCell::DBCell

(

DBCell &&

from

)

move constructor

References DBCell().

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~DBCell()

gum::learning::DBCell::~DBCell

(

)

destructor

Member Function Documentation

bestDBCell()

DBCell gum::learning::DBCell::bestDBCell ( std::string_view str, const std::vector< std::string > & missingVals )

static

returns the DBCell with the best type for an element encoded as a string

Parameters

str	the string to convert into a DBCell
missingVals	a vector containing the set of strings that should be interpreted as missing values. Whenever str matches one these strings, the returned DBCell represents a missing value.

References DBCell(), and bestDBCell().

Referenced by bestDBCell().

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bestType()

EltType gum::learning::DBCell::bestType ( std::string_view str, const std::vector< std::string > & missingVals )

static

returns the best type to store a given element encoded as a string

Parameters

str	the string to convert into a DBCell
missingVals	a vector containing the set of strings that should be interpreted as missing values. Whenever str matches one these strings, the returned EltType represents a missing value.

References bestType().

Referenced by bestType().

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convertType()

bool gum::learning::DBCell::convertType

(

const EltType

newtype

)

try to convert the content of the DBCell into another type

Returns

true if the conversion has been successfully performed.

References convertType().

Referenced by convertType().

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integer()

int gum::learning::DBCell::integer

(

)

const

returns the DBcell as an integer

Warning

if the cell is not of type INTEGER, the dbcell will not try to convert its content into a float, it will raise a TypeError exception.

Exceptions

TypeError

if the DBCell is not labelled as type INTEGER

References integer().

Referenced by integer().

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isInteger()

bool gum::learning::DBCell::isInteger ( std::string_view str )

static

determines whether a string corresponds precisely to an integer

References isInteger().

Referenced by isInteger().

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isMissing() [1/2]

bool gum::learning::DBCell::isMissing

(

)

const

indicates whether the cell contains a missing value

References isMissing().

Referenced by isMissing(), and isMissing().

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isMissing() [2/2]

bool gum::learning::DBCell::isMissing ( std::string_view str, const std::vector< std::string > & missingVals )

static

checks whether a string correspond to a missing value

References isMissing(), and MISSING.

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isReal()

bool gum::learning::DBCell::isReal ( std::string_view str )

static

determine whether a string corresponds precisely to a real number

References isReal().

Referenced by isReal().

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operator=() [1/5]

DBCell & gum::learning::DBCell::operator=

(

const DBCell &

from

)

copy operator

References DBCell().

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operator=() [2/5]

DBCell & gum::learning::DBCell::operator=

(

const float

x

)

assignment operator

References DBCell().

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operator=() [3/5]

DBCell & gum::learning::DBCell::operator=

(

const int

x

)

assignment operator

References DBCell().

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operator=() [4/5]

DBCell & gum::learning::DBCell::operator=

(

const std::string &

x

)

assignment operator

References DBCell().

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operator=() [5/5]

DBCell & gum::learning::DBCell::operator=

(

DBCell &&

from

)

move operator

References DBCell().

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operator==()

bool gum::learning::DBCell::operator==

(

const DBCell &

from

)

const

test of equality

References DBCell().

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real()

float gum::learning::DBCell::real

(

)

const

returns the DBcell as a real number

Warning

if the cell is not of type REAL, the dbcell will not try to convert its content into a real number, it will raise a TypeError exception.

Returns

the content of the DBCell (if this is a real number)

Exceptions

TypeError

if the DBCell is not labelled as type REAL

References real().

Referenced by real().

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setInteger() [1/2]

void gum::learning::DBCell::setInteger

(

const int

x

)

sets the content of the DBCell

References setInteger().

Referenced by setInteger(), and setInteger().

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setInteger() [2/2]

void gum::learning::DBCell::setInteger

(

std::string_view

elt

)

sets the content of the DBCell from a string

Exceptions

TypeError

if the string does not correspond to an integer

References setInteger().

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setMissingState()

void gum::learning::DBCell::setMissingState

(

)

sets the DBCell as a missing element

References setMissingState().

Referenced by setMissingState().

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setReal() [1/2]

void gum::learning::DBCell::setReal

(

const float

x

)

sets the content of the DBCell

References setReal().

Referenced by setReal(), and setReal().

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setReal() [2/2]

void gum::learning::DBCell::setReal

(

std::string_view

elt

)

sets the content of the DBCell from a string

Exceptions

TypeError

if the string does not correspond to a real number

References setReal().

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setString()

void gum::learning::DBCell::setString

(

const std::string &

elt

)

sets the content of the DBCell

References setString().

Referenced by setString().

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string() [1/2]

const std::string & gum::learning::DBCell::string

(

)

const

returns the DBcell as a string

Warning

if the cell is not of type STRING, the dbcell will not try to convert its content into a string, it will raise a TypeError exception.

Exceptions

TypeError

if the DBCell is not labelled as type STRING

string() [2/2]

const std::string & gum::learning::DBCell::string ( const int index )

static

strings are stored into a static bijection. Get its ith string

Exceptions

UndefinedElement

if the index does not correspond to any string

stringIndex()

int gum::learning::DBCell::stringIndex

(

)

const

returns the DBcell as the index of a string in a static bijection

All strings referenced by DBCells are stored in a bijection. This method returns the index of the string referenced by the current DBCell.

Exceptions

TypeError

if the DBCell is not labelled as type STRING

References stringIndex().

Referenced by stringIndex().

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toString()

std::string gum::learning::DBCell::toString

(

const std::vector< std::string > &

missingVals

)

const

returns the content of the DBCell as a string, whatever its type

Exceptions

UndefinedElement

is raised if the DBCell corresponds to a missing value but the set of missing values passed in argument is empty.

References toString().

Referenced by toString().

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type()

EltType gum::learning::DBCell::type ( ) const

noexcept

returns the current type of the DBCell

---

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

• agrum/base/database/DBCell.h