The feature class encapsulates a single feature including its unique ID, geometry and a list of field/values attributes. More...

#include <qgsfeature.h>

Public Member Functions
	QgsFeature (const QgsFeature &rhs)
	QgsFeature (const QgsFields &fields, QgsFeatureId id=FID_NULL)
	Constructor for QgsFeature.
	QgsFeature (QgsFeatureId id=FID_NULL)
	Constructor for QgsFeature.
virtual	~QgsFeature ()
int	approximateMemoryUsage () const
	Returns the approximate RAM usage of the feature, in bytes.
Q_INVOKABLE QVariant	attribute (const QString &name) const
	Lookup attribute value by attribute name.
QVariant	attribute (int fieldIdx) const
	Lookup attribute value from its index.
int	attributeCount () const
	Returns the number of attributes attached to the feature.
QVariantMap	attributeMap () const
	Returns the feature's attributes as a map of field name to value.
QgsAttributes	attributes () const
	Returns the feature's attributes.
void	clearGeometry ()
	Removes any geometry associated with the feature.
bool	deleteAttribute (const QString &name)
	Clear's an attribute's value by its field name.
void	deleteAttribute (int field)
	Clear's an attribute's value by its index.
const QgsSymbol *	embeddedSymbol () const
	Returns the feature's embedded symbology, or `nullptr` if the feature has no embedded symbol.
int	fieldNameIndex (const QString &fieldName) const
	Utility method to get attribute index from name.
QgsFields	fields () const
	Returns the field map associated with the feature.
QgsGeometry	geometry () const
	Returns the geometry associated with this feature.
bool	hasGeometry () const
	Returns `true` if the feature has an associated geometry.
QgsFeatureId	id () const
	Returns the feature ID for this feature.
void	initAttributes (int fieldCount)
	Initialize this feature with the given number of fields.
bool	isUnsetValue (int fieldIdx) const
	Returns `true` if the attribute at the specified index is an unset value.
bool	isValid () const
	Returns the validity of this feature.
	operator QVariant () const
	Allows direct construction of QVariants from features.
bool	operator!= (const QgsFeature &other) const
QgsFeature &	operator= (const QgsFeature &rhs)
bool	operator== (const QgsFeature &other) const
void	padAttributes (int count)
	Resizes the attributes attached to this feature by appending the specified count of NULL values to the end of the existing attributes.
void	resizeAttributes (int fieldCount)
	Resizes the attributes attached to this feature to the given number of fields.
Q_INVOKABLE bool	setAttribute (const QString &name, const QVariant &value)
	Insert a value into attribute, by field name.
Q_INVOKABLE bool	setAttribute (int field, const QVariant &attr)
	Sets an attribute's value by field index.
void	setAttributes (const QgsAttributes &attrs)
	Sets the feature's attributes.
void	setEmbeddedSymbol (QgsSymbol *symbol)
	Sets the feature's embedded symbol.
void	setFields (const QgsFields &fields, bool initAttributes=false)
	Assigns a field map with the feature to allow attribute access by attribute name.
void	setGeometry (const QgsGeometry &geometry)
	Set the feature's geometry.
void	setGeometry (std::unique_ptr< QgsAbstractGeometry > geometry)
	Set the feature's geometry.
void	setId (QgsFeatureId id)
	Sets the feature id for this feature.
void	setValid (bool validity)
	Sets the validity of the feature.

Properties
QgsAttributes	attributes
QgsFields	fields
QgsGeometry	geometry
QgsFeatureId	id

Detailed Description

The feature class encapsulates a single feature including its unique ID, geometry and a list of field/values attributes.

Note: QgsFeature objects are implicitly shared.

Definition at line 59 of file qgsfeature.h.

Constructor & Destructor Documentation

◆ QgsFeature() [1/3]

QgsFeature::QgsFeature ( QgsFeatureId id = FID_NULL )

Constructor for QgsFeature.

Parameters

id	unique feature ID

Definition at line 45 of file qgsfeature.cpp.

◆ QgsFeature() [2/3]

QgsFeature::QgsFeature	(	const QgsFields &	fields,
		QgsFeatureId	id = FID_NULL )

Constructor for QgsFeature.

Parameters

fields	feature's fields
id	unique feature ID

Definition at line 50 of file qgsfeature.cpp.

◆ QgsFeature() [3/3]

QgsFeature::QgsFeature ( const QgsFeature & rhs )

Definition at line 57 of file qgsfeature.cpp.

◆ ~QgsFeature()

QgsFeature::~QgsFeature ( )

virtual

Definition at line 94 of file qgsfeature.cpp.

Member Function Documentation

◆ approximateMemoryUsage()

int QgsFeature::approximateMemoryUsage ( ) const

Returns the approximate RAM usage of the feature, in bytes.

This method takes into account the size of variable elements (strings, geometry, ...), but the value returned should be considered as a lower bound estimation.

Since: QGIS 3.16

Definition at line 385 of file qgsfeature.cpp.

◆ attribute() [1/2]

QVariant QgsFeature::attribute ( const QString & name ) const

Lookup attribute value by attribute name.

Field map must be associated using setFields() before this method can be used.

Parameters

name	The name of the attribute to get

Returns: The value of the attribute, or an invalid/null variant if no such name exists

See also: setFields

Definition at line 338 of file qgsfeature.cpp.

◆ attribute() [2/2]

QVariant QgsFeature::attribute ( int fieldIdx ) const

Lookup attribute value from its index.

Parameters

fieldIdx The index of the attribute to get

Returns: The value of the attribute, or an invalid/null variant if no such name exists

See also: setFields()

Definition at line 308 of file qgsfeature.cpp.

◆ attributeCount()

int QgsFeature::attributeCount ( ) const

Returns the number of attributes attached to the feature.

Since: QGIS 3.18

Definition at line 158 of file qgsfeature.cpp.

◆ attributeMap()

QVariantMap QgsFeature::attributeMap ( ) const

Returns the feature's attributes as a map of field name to value.

Note: The fields definition must be associated with the feature using setFields() before this method can be used.

See also: attributes(); setAttributes()

Since: QGIS 3.22.2

Definition at line 140 of file qgsfeature.cpp.

◆ attributes()

QgsAttributes QgsFeature::attributes ( ) const

Returns the feature's attributes.

Alternatively, in Python it is possible to directly iterate over a feature in order to retrieve its attributes:

feature = QgsFeature()
feature.setAttributes([11, 'string value', 55.5])
for attr in feature:
    print(attr)

See also: setAttributes(); attributeMap()

Definition at line 135 of file qgsfeature.cpp.

◆ clearGeometry()

void QgsFeature::clearGeometry ( )

Removes any geometry associated with the feature.

See also: setGeometry(); hasGeometry()

Definition at line 184 of file qgsfeature.cpp.

◆ deleteAttribute() [1/2]

bool QgsFeature::deleteAttribute ( const QString & name )

Clear's an attribute's value by its field name.

Field map must be associated using setFields() before this method can be used.

Parameters

name	The name of the field to clear

Returns: false if attribute name could not be converted to index

See also: setFields()

Definition at line 297 of file qgsfeature.cpp.

◆ deleteAttribute() [2/2]

void QgsFeature::deleteAttribute ( int field )

Clear's an attribute's value by its index.

Parameters

field the index of the field

See also: setAttribute()

Definition at line 108 of file qgsfeature.cpp.

◆ embeddedSymbol()

const QgsSymbol * QgsFeature::embeddedSymbol ( ) const

Returns the feature's embedded symbology, or nullptr if the feature has no embedded symbol.

Since: QGIS 3.20

Definition at line 324 of file qgsfeature.cpp.

◆ fieldNameIndex()

int QgsFeature::fieldNameIndex ( const QString & fieldName ) const

Utility method to get attribute index from name.

Field map must be associated using setFields() before this method can be used.

Parameters

fieldName name of field to get attribute index of

Returns: -1 if field does not exist or field map is not associated.

See also: setFields()

Definition at line 353 of file qgsfeature.cpp.

◆ fields()

QgsFields QgsFeature::fields ( ) const

Returns the field map associated with the feature.

See also: setFields()

Definition at line 208 of file qgsfeature.cpp.

◆ geometry()

QgsGeometry QgsFeature::geometry ( ) const

Returns the geometry associated with this feature.

If the feature has no geometry, an empty QgsGeometry object will be returned.

See also: hasGeometry(); setGeometry()

Definition at line 114 of file qgsfeature.cpp.

◆ hasGeometry()

bool QgsFeature::hasGeometry ( ) const

Returns true if the feature has an associated geometry.

See also: geometry()

Definition at line 233 of file qgsfeature.cpp.

◆ id()

QgsFeatureId QgsFeature::id ( ) const

Returns the feature ID for this feature.

See also: setId()

Definition at line 103 of file qgsfeature.cpp.

◆ initAttributes()

void QgsFeature::initAttributes ( int fieldCount )

Initialize this feature with the given number of fields.

Discards any previously set attribute data.

Parameters

fieldCount Number of fields to initialize

See also: resizeAttributes()

Definition at line 238 of file qgsfeature.cpp.

◆ isUnsetValue()

bool QgsFeature::isUnsetValue ( int fieldIdx ) const

Returns true if the attribute at the specified index is an unset value.

See also: QgsUnsetAttributeValue

Since: QGIS 3.28

Definition at line 316 of file qgsfeature.cpp.

◆ isValid()

bool QgsFeature::isValid ( ) const

Returns the validity of this feature.

This is normally set by the provider to indicate some problem that makes the feature invalid or to indicate a null feature.

See also: setValid()

Definition at line 219 of file qgsfeature.cpp.

◆ operator QVariant()

QgsFeature::operator QVariant ( ) const

inline

Allows direct construction of QVariants from features.

Definition at line 1262 of file qgsfeature.h.

◆ operator!=()

bool QgsFeature::operator!= ( const QgsFeature & other ) const

Definition at line 89 of file qgsfeature.cpp.

◆ operator=()

QgsFeature & QgsFeature::operator= ( const QgsFeature & rhs )

Definition at line 61 of file qgsfeature.cpp.

◆ operator==()

bool QgsFeature::operator== ( const QgsFeature & other ) const

Definition at line 70 of file qgsfeature.cpp.

◆ padAttributes()

void QgsFeature::padAttributes ( int count )

Resizes the attributes attached to this feature by appending the specified count of NULL values to the end of the existing attributes.

See also: resizeAttributes()

Since: QGIS 3.18

Definition at line 256 of file qgsfeature.cpp.

◆ resizeAttributes()

void QgsFeature::resizeAttributes ( int fieldCount )

Resizes the attributes attached to this feature to the given number of fields.

If the new fieldCount is greater than the original number of fields then the additional attributes will be filled with NULL values. All existing attributes will remain unchanged.

If the new fieldCount is less than the original number of fields then the unwanted values will be discarded from the end of the existing attributes.

See also: initAttributes(); padAttributes()

Since: QGIS 3.18

Definition at line 247 of file qgsfeature.cpp.

◆ setAttribute() [1/2]

bool QgsFeature::setAttribute	(	const QString &	name,
		const QVariant &	value )

Insert a value into attribute, by field name.

Returns false if field name could not be matched.

Field map must be associated using setFields() before this method can be used.

Calling this method will automatically set the feature as valid (see isValid()).

Parameters

name	The name of the field to set
value	The value to set

Returns: false if attribute name could not be converted to index

See also: setFields()

Definition at line 285 of file qgsfeature.cpp.

◆ setAttribute() [2/2]

bool QgsFeature::setAttribute	(	int	field,
		const QVariant &	attr )

Sets an attribute's value by field index.

If the attribute was successfully set then the feature will be automatically marked as valid (see isValid()).

Parameters

field	the index of the field to set
attr	the value of the attribute

Returns: false, if the field index does not exist

See also: setAttributes()

Definition at line 265 of file qgsfeature.cpp.

◆ setAttributes()

void QgsFeature::setAttributes ( const QgsAttributes & attrs )

Sets the feature's attributes.

Calling this method will automatically set the feature as valid (see isValid()).

The number of provided attributes need to exactly match the number of the feature's fields.

Parameters

attrs List of attribute values

Warning: If the number of provided attributes does not exactly match the number of the feature's fields then it will not be possible to add this feature to the corresponding data provider.

See also: setAttribute(); attributes()

Definition at line 163 of file qgsfeature.cpp.

◆ setEmbeddedSymbol()

void QgsFeature::setEmbeddedSymbol ( QgsSymbol * symbol )

Sets the feature's embedded symbol.

Ownership of symbol is transferred to the feature.

Since: QGIS 3.20

Definition at line 329 of file qgsfeature.cpp.

◆ setFields()

void QgsFeature::setFields	(	const QgsFields &	fields,
		bool	initAttributes = false )

Assigns a field map with the feature to allow attribute access by attribute name.

Parameters

fields	The attribute fields which this feature holds
initAttributes	If `true`, attributes are initialized. Clears any data previously assigned.

See also: fields()

Definition at line 198 of file qgsfeature.cpp.

◆ setGeometry() [1/2]

void QgsFeature::setGeometry ( const QgsGeometry & geometry )

Set the feature's geometry.

Calling this method will automatically set the feature as valid (see isValid()).

Parameters

geometry new feature geometry

See also: geometry(); clearGeometry()

Definition at line 170 of file qgsfeature.cpp.

◆ setGeometry() [2/2]

void QgsFeature::setGeometry ( std::unique_ptr< QgsAbstractGeometry > geometry )

Set the feature's geometry.

Ownership of the geometry is transferred to the feature.

Calling this method will automatically set the feature as valid (see isValid()).

This method is a shortcut for calling:

feature.setGeometry( QgsGeometry( geometry ) )

QgsGeometry

A geometry is the spatial representation of a feature.

Definition qgsgeometry.h:178

Example

# Sets a feature's geometry to a point geometry
feature.setGeometry( QgsPoint( 210, 41 ) )
print(feature.geometry())
# output: <QgsGeometry: Point (210 41)>
 
# Sets a feature's geometry to a line string
feature.setGeometry( QgsLineString( [ QgsPoint( 210, 41 ), QgsPoint( 301, 55 ) ] ) )
print(feature.geometry())
# output: <QgsGeometry: LineString (210 41, 301 55)>

See also: geometry(); clearGeometry()

Since: QGIS 3.6

Definition at line 177 of file qgsfeature.cpp.

◆ setId()

void QgsFeature::setId ( QgsFeatureId id )

Sets the feature id for this feature.

Parameters

id	feature id

See also: id()

Warning: Feature IDs will be automatically changed whenever a feature is added to vector layer or data provider. This method is not designed to allow a specific feature ID to be assigned to a feature which will be added to a layer or data provider, and the results will be unpredictable

Definition at line 125 of file qgsfeature.cpp.

◆ setValid()

void QgsFeature::setValid ( bool validity )

Sets the validity of the feature.

Parameters

validity set to true if feature is valid

See also: isValid()

Definition at line 224 of file qgsfeature.cpp.

Property Documentation

◆ attributes

QgsAttributes QgsFeature::attributes

readwrite

Definition at line 69 of file qgsfeature.h.

◆ fields

QgsFields QgsFeature::fields

readwrite

Definition at line 70 of file qgsfeature.h.

◆ geometry

QgsGeometry QgsFeature::geometry

readwrite

Definition at line 71 of file qgsfeature.h.

◆ id

QgsFeatureId QgsFeature::id

readwrite

Definition at line 68 of file qgsfeature.h.

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

/build/qgis-4.0.0+99sid/src/core/qgsfeature.h
/build/qgis-4.0.0+99sid/src/core/qgsfeature.cpp

Public Member Functions

Properties

Detailed Description

Constructor & Destructor Documentation

◆ QgsFeature() [1/3]

◆ QgsFeature() [2/3]

◆ QgsFeature() [3/3]

◆ ~QgsFeature()

Member Function Documentation

◆ approximateMemoryUsage()

◆ attribute() [1/2]

◆ attribute() [2/2]

◆ attributeCount()

◆ attributeMap()

◆ attributes()

◆ clearGeometry()

◆ deleteAttribute() [1/2]

◆ deleteAttribute() [2/2]

◆ embeddedSymbol()

◆ fieldNameIndex()

◆ fields()

◆ geometry()

◆ hasGeometry()

◆ id()

◆ initAttributes()

◆ isUnsetValue()

◆ isValid()

◆ operator QVariant()

◆ operator!=()

◆ operator=()

◆ operator==()

◆ padAttributes()

◆ resizeAttributes()

◆ setAttribute() [1/2]

◆ setAttribute() [2/2]

◆ setAttributes()

◆ setEmbeddedSymbol()

◆ setFields()

◆ setGeometry() [1/2]

◆ setGeometry() [2/2]

Example

◆ setId()

◆ setValid()

Property Documentation

◆ attributes

◆ fields

◆ geometry

◆ id