Container of fields for a vector layer. More...

#include <qgsfields.h>

Classes
struct	Field

Public Types
typedef struct QgsFields::Field	Field

enum	FieldOrigin { OriginUnknown , OriginProvider , OriginJoin , OriginEdit , OriginExpression }

Public Member Functions
	QgsFields ()
	Constructor for an empty field container.

	QgsFields (const QgsFields &other)
	Copy constructor.

virtual	~QgsFields ()

QgsAttributeList	allAttributesList () const
	Utility function to get list of attribute indexes.

bool	append (const QgsField &field, FieldOrigin origin=OriginProvider, int originIndex=-1)
	Appends a field. The field must have unique name, otherwise it is rejected (returns `false`)

bool	appendExpressionField (const QgsField &field, int originIndex)
	Appends an expression field. The field must have unique name, otherwise it is rejected (returns `false`)

QgsField	at (int i) const
	Returns the field at particular index (must be in range 0..N-1).

iterator	begin ()
	Returns an STL-style iterator pointing to the first item in the list.

const_iterator	begin () const noexcept
	Returns a const STL-style iterator pointing to the first item in the list.

void	clear ()
	Removes all fields.

const_iterator	constBegin () const noexcept
	Returns a const STL-style iterator pointing to the first item in the list.

const_iterator	constEnd () const noexcept
	Returns a const STL-style iterator pointing to the imaginary item after the last item in the list.

int	count () const
	Returns number of items.

iterator	end ()
	Returns an STL-style iterator pointing to the imaginary item after the last item in the list.

const_iterator	end () const noexcept
	Returns a const STL-style iterator pointing to the imaginary item after the last item in the list.

bool	exists (int i) const
	Returns if a field index is valid.

void	extend (const QgsFields &other)
	Extends with fields from another QgsFields container.

QgsField	field (const QString &name) const
	Returns the field with matching name.

QgsField	field (int fieldIdx) const
	Returns the field at particular index (must be in range 0..N-1).

FieldOrigin	fieldOrigin (int fieldIdx) const
	Returns the field's origin (value from an enumeration).

int	fieldOriginIndex (int fieldIdx) const
	Returns the field's origin index (its meaning is specific to each type of origin).

QIcon	iconForField (int fieldIdx, bool considerOrigin=false) const
	Returns an icon corresponding to a field index, based on the field's type and source.

int	indexFromName (const QString &fieldName) const
	Gets the field index from the field name.

int	indexOf (const QString &fieldName) const
	Gets the field index from the field name.

bool	isEmpty () const
	Checks whether the container is empty.

int	lookupField (const QString &fieldName) const
	Looks up field's index from the field name.

QStringList	names () const
	Returns a list with field names.

	operator QVariant () const
	Allows direct construction of QVariants from fields.

bool	operator!= (const QgsFields &other) const

QgsFields &	operator= (const QgsFields &other)
	Assignment operator.

bool	operator== (const QgsFields &other) const

QgsField &	operator[] (int i)
	Gets field at particular index (must be in range 0..N-1)

QgsField	operator[] (int i) const
	Gets field at particular index (must be in range 0..N-1)

void	remove (int fieldIdx)
	Removes the field with the given index.

bool	rename (int fieldIdx, const QString &name)
	Renames a name of field.

int	size () const
	Returns number of items.

QList< QgsField >	toList () const
	Utility function to return a list of QgsField instances.

Static Public Member Functions
static QIcon	iconForFieldType (QVariant::Type type, QVariant::Type subType=QVariant::Type::Invalid, const QString &typeString=QString())
	Returns an icon corresponding to a field type.

Detailed Description

Container of fields for a vector layer.

In addition to storing a list of QgsField instances, it also:

allows quick lookups of field names to index in the list
keeps track of where the field definition comes from (vector data provider, joined layer or newly added from an editing operation)

Note: QgsFields objects are implicitly shared.

Definition at line 44 of file qgsfields.h.

Member Typedef Documentation

◆ Field

typedef struct QgsFields::Field QgsFields::Field

Member Enumeration Documentation

◆ FieldOrigin

enum QgsFields::FieldOrigin

Enumerator
OriginUnknown	It has not been specified where the field comes from.
OriginProvider	Field comes from the underlying data provider of the vector layer (originIndex = index in provider's fields)
OriginJoin	Field comes from a joined layer (originIndex / 1000 = index of the join, originIndex % 1000 = index within the join)
OriginEdit	Field has been temporarily added in editing mode (originIndex = index in the list of added attributes)
OriginExpression	Field is calculated from an expression.

Definition at line 48 of file qgsfields.h.

Constructor & Destructor Documentation

◆ QgsFields() [1/2]

QgsFields::QgsFields ( )

Constructor for an empty field container.

Definition at line 28 of file qgsfields.cpp.

◆ QgsFields() [2/2]

QgsFields::QgsFields ( const QgsFields & other )

Copy constructor.

Definition at line 33 of file qgsfields.cpp.

◆ ~QgsFields()

QgsFields::~QgsFields ( )

virtual

Definition at line 44 of file qgsfields.cpp.

Member Function Documentation

◆ allAttributesList()

QgsAttributeList QgsFields::allAttributesList ( ) const

Utility function to get list of attribute indexes.

Definition at line 386 of file qgsfields.cpp.

◆ append()

bool QgsFields::append	(	const QgsField &	field,
		FieldOrigin	origin = `OriginProvider`,
		int	originIndex = `-1`
	)

Appends a field. The field must have unique name, otherwise it is rejected (returns false)

Definition at line 59 of file qgsfields.cpp.

◆ appendExpressionField()

bool QgsFields::appendExpressionField	(	const QgsField &	field,
		int	originIndex
	)

Appends an expression field. The field must have unique name, otherwise it is rejected (returns false)

Definition at line 90 of file qgsfields.cpp.

◆ at()

QgsField QgsFields::at ( int i ) const

Returns the field at particular index (must be in range 0..N-1).

Definition at line 163 of file qgsfields.cpp.

◆ begin() [1/2]

QgsFields::iterator QgsFields::begin ( )

Returns an STL-style iterator pointing to the first item in the list.

Note: not available in Python bindings

Definition at line 257 of file qgsfields.cpp.

◆ begin() [2/2]

QgsFields::const_iterator QgsFields::begin ( ) const

noexcept

Returns a const STL-style iterator pointing to the first item in the list.

Note: not available in Python bindings

Definition at line 241 of file qgsfields.cpp.

◆ clear()

void QgsFields::clear ( )

Removes all fields.

Definition at line 47 of file qgsfields.cpp.

◆ constBegin()

QgsFields::const_iterator QgsFields::constBegin ( ) const

noexcept

Returns a const STL-style iterator pointing to the first item in the list.

Note: not available in Python bindings

Definition at line 225 of file qgsfields.cpp.

◆ constEnd()

QgsFields::const_iterator QgsFields::constEnd ( ) const

noexcept

Returns a const STL-style iterator pointing to the imaginary item after the last item in the list.

Note: not available in Python bindings

Definition at line 233 of file qgsfields.cpp.

◆ count()

int QgsFields::count ( ) const

Returns number of items.

Definition at line 133 of file qgsfields.cpp.

◆ end() [1/2]

QgsFields::iterator QgsFields::end ( )

Returns an STL-style iterator pointing to the imaginary item after the last item in the list.

Note: not available in Python bindings

Definition at line 266 of file qgsfields.cpp.

◆ end() [2/2]

QgsFields::const_iterator QgsFields::end ( ) const

noexcept

Returns a const STL-style iterator pointing to the imaginary item after the last item in the list.

Note: not available in Python bindings

Definition at line 249 of file qgsfields.cpp.

◆ exists()

bool QgsFields::exists ( int i ) const

Returns if a field index is valid.

Parameters

i	Index of the field which needs to be checked

Returns: true if the field exists

Definition at line 153 of file qgsfields.cpp.

◆ extend()

void QgsFields::extend ( const QgsFields & other )

Extends with fields from another QgsFields container.

Definition at line 114 of file qgsfields.cpp.

◆ field() [1/2]

QgsField QgsFields::field ( const QString & name ) const

Returns the field with matching name.

Definition at line 173 of file qgsfields.cpp.

◆ field() [2/2]

QgsField QgsFields::field ( int fieldIdx ) const

Returns the field at particular index (must be in range 0..N-1).

Definition at line 168 of file qgsfields.cpp.

◆ fieldOrigin()

QgsFields::FieldOrigin QgsFields::fieldOrigin ( int fieldIdx ) const

Returns the field's origin (value from an enumeration).

Definition at line 189 of file qgsfields.cpp.

◆ fieldOriginIndex()

int QgsFields::fieldOriginIndex ( int fieldIdx ) const

Returns the field's origin index (its meaning is specific to each type of origin).

Definition at line 197 of file qgsfields.cpp.

◆ iconForField()

QIcon QgsFields::iconForField	(	int	fieldIdx,
		bool	considerOrigin = `false`
	)		const

Returns an icon corresponding to a field index, based on the field's type and source.

Parameters

fieldIdx	the field index
considerOrigin	if `true` the icon will the origin of the field

Definition at line 275 of file qgsfields.cpp.

◆ iconForFieldType()

QIcon QgsFields::iconForFieldType	(	QVariant::Type	type,
		QVariant::Type	subType = `QVariant::Type::Invalid`,
		const QString &	typeString = `QString()`
	)

static

Returns an icon corresponding to a field type.

Since QGIS 3.24, the optional subType argument can be used to specify the type of variant list or map values. Since QGIS 3.30, the optional typeString argument can be used to specify field type strings for handling user field types.

Since: QGIS 3.16

Definition at line 294 of file qgsfields.cpp.

◆ indexFromName()

int QgsFields::indexFromName ( const QString & fieldName ) const

Gets the field index from the field name.

This method is case sensitive and only matches the data source name of the field.

Alias for indexOf

Parameters

fieldName The name of the field.

Returns: The field index if found or -1 in case it cannot be found.

See also: lookupField For a more tolerant alternative.

Definition at line 202 of file qgsfields.cpp.

◆ indexOf()

int QgsFields::indexOf ( const QString & fieldName ) const

Gets the field index from the field name.

This method is case sensitive and only matches the data source name of the field.

Parameters

fieldName The name of the field.

Returns: The field index if found or -1 in case it cannot be found.

See also: lookupField For a more tolerant alternative.

Definition at line 207 of file qgsfields.cpp.

◆ isEmpty()

bool QgsFields::isEmpty ( ) const

Checks whether the container is empty.

Definition at line 128 of file qgsfields.cpp.

◆ lookupField()

int QgsFields::lookupField ( const QString & fieldName ) const

Looks up field's index from the field name.

This method matches in the following order:

The exact field name taking case sensitivity into account
Looks for the field name by case insensitive comparison
The field alias (case insensitive)

Parameters

fieldName The name to look for.

Returns: The field index if found or -1 in case it cannot be found.

See also: indexFromName For a more performant and precise but less tolerant alternative.

Definition at line 359 of file qgsfields.cpp.

◆ names()

QStringList QgsFields::names ( ) const

Returns a list with field names.

Definition at line 143 of file qgsfields.cpp.

◆ operator QVariant()

QgsFields::operator QVariant ( ) const

inline

Allows direct construction of QVariants from fields.

Definition at line 439 of file qgsfields.h.

◆ operator!=()

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

inline

Definition at line 396 of file qgsfields.h.

◆ operator=()

QgsFields & QgsFields::operator= ( const QgsFields & other )

Assignment operator.

Definition at line 38 of file qgsfields.cpp.

◆ operator==()

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

Definition at line 220 of file qgsfields.cpp.

◆ operator[]() [1/2]

QgsField & QgsFields::operator[] ( int i )

Gets field at particular index (must be in range 0..N-1)

Definition at line 158 of file qgsfields.cpp.

◆ operator[]() [2/2]

QgsField QgsFields::operator[] ( int i ) const

Gets field at particular index (must be in range 0..N-1)

Definition at line 184 of file qgsfields.cpp.

◆ remove()

void QgsFields::remove ( int fieldIdx )

Removes the field with the given index.

Definition at line 101 of file qgsfields.cpp.

◆ rename()

bool QgsFields::rename	(	int	fieldIdx,
		const QString &	name
	)

Renames a name of field.

The field must have unique name, otherwise change is rejected (returns false)

Since: QGIS 3.6

Definition at line 72 of file qgsfields.cpp.

◆ size()

int QgsFields::size ( ) const

Returns number of items.

Definition at line 138 of file qgsfields.cpp.

◆ toList()

QList< QgsField > QgsFields::toList ( ) const

Utility function to return a list of QgsField instances.

Definition at line 212 of file qgsfields.cpp.

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

/build/qgis-3.36.0+99sid/src/core/qgsfields.h
/build/qgis-3.36.0+99sid/src/core/qgsfields.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Typedef Documentation

◆ Field

Member Enumeration Documentation

◆ FieldOrigin

Constructor & Destructor Documentation

◆ QgsFields() [1/2]

◆ QgsFields() [2/2]

◆ ~QgsFields()

Member Function Documentation

◆ allAttributesList()

◆ append()

◆ appendExpressionField()

◆ at()

◆ begin() [1/2]

◆ begin() [2/2]

◆ clear()

◆ constBegin()

◆ constEnd()

◆ count()

◆ end() [1/2]

◆ end() [2/2]

◆ exists()

◆ extend()

◆ field() [1/2]

◆ field() [2/2]

◆ fieldOrigin()

◆ fieldOriginIndex()

◆ iconForField()

◆ iconForFieldType()

◆ indexFromName()

◆ indexOf()

◆ isEmpty()

◆ lookupField()

◆ names()

◆ operator QVariant()

◆ operator!=()

◆ operator=()

◆ operator==()

◆ operator[]() [1/2]

◆ operator[]() [2/2]

◆ remove()

◆ rename()

◆ size()

◆ toList()