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

#include <qgsfields.h>

Classes
struct	Field

Public Types
typedef struct QgsFields::Field	Field

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, Qgis::FieldOrigin origin=Qgis::FieldOrigin::Provider, int originIndex=-1)
	Appends a field.

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.

Q_INVOKABLE 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).

Qgis::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.

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

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

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

Q_INVOKABLE 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 (QMetaType::Type type, QMetaType::Type subType=QMetaType::Type::UnknownType, const QString &typeString=QString())
	Returns an icon corresponding to a field type.

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

Properties
int	count

bool	isEmpty

QStringList	names

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 45 of file qgsfields.h.

Member Typedef Documentation

◆ Field

typedef struct QgsFields::Field QgsFields::Field

Constructor & Destructor Documentation

◆ QgsFields() [1/2]

QgsFields::QgsFields ( )

Constructor for an empty field container.

Definition at line 29 of file qgsfields.cpp.

◆ QgsFields() [2/2]

QgsFields::QgsFields ( const QgsFields & other )

Copy constructor.

Definition at line 34 of file qgsfields.cpp.

◆ ~QgsFields()

QgsFields::~QgsFields ( )

virtual

Definition at line 45 of file qgsfields.cpp.

Member Function Documentation

◆ allAttributesList()

QgsAttributeList QgsFields::allAttributesList ( ) const

Utility function to get list of attribute indexes.

Definition at line 392 of file qgsfields.cpp.

◆ append()

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

Appends a field.

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

The originIndex argument must be set to a value corresponding to the origin type:

Qgis::FieldOrigin::Provider: The field's originIndex is the index in provider's fields.
Qgis::FieldOrigin::Join: The field's originIndex / 1000 = index of the join, originIndex % 1000 = index within the join
Qgis::FieldOrigin::Edit: The originIndex is the index in the list of added attributes

Definition at line 60 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 91 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 164 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 258 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 242 of file qgsfields.cpp.

◆ clear()

void QgsFields::clear ( )

Removes all fields.

Definition at line 48 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 226 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 234 of file qgsfields.cpp.

◆ count()

int QgsFields::count ( ) const

Returns number of items.

Definition at line 134 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 267 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 250 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 154 of file qgsfields.cpp.

◆ extend()

void QgsFields::extend ( const QgsFields & other )

Extends with fields from another QgsFields container.

Definition at line 115 of file qgsfields.cpp.

◆ field() [1/2]

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

Returns the field with matching name.

Definition at line 174 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 169 of file qgsfields.cpp.

◆ fieldOrigin()

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

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

Definition at line 190 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).

Qgis::FieldOrigin::Provider: The field's originIndex is the index in provider's fields.
Qgis::FieldOrigin::Join: The field's originIndex / 1000 = index of the join, originIndex % 1000 = index within the join
Qgis::FieldOrigin::Edit: The originIndex is the index in the list of added attributes

Definition at line 198 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 276 of file qgsfields.cpp.

◆ iconForFieldType() [1/2]

QIcon QgsFields::iconForFieldType	(	QMetaType::Type	type,
		QMetaType::Type	subType = `QMetaType::Type::UnknownType`,
		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 295 of file qgsfields.cpp.

◆ iconForFieldType() [2/2]

QIcon QgsFields::iconForFieldType	(	QVariant::Type	type,
		QVariant::Type	subType,
		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

Deprecated:: since QGIS 3.38, use the method with a QMetaType::Type argument instead

Definition at line 354 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 203 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 208 of file qgsfields.cpp.

◆ isEmpty()

bool QgsFields::isEmpty ( ) const

Checks whether the container is empty.

Definition at line 129 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 365 of file qgsfields.cpp.

◆ names()

QStringList QgsFields::names ( ) const

Returns a list with field names.

Definition at line 144 of file qgsfields.cpp.

◆ operator QVariant()

QgsFields::operator QVariant ( ) const

inline

Allows direct construction of QVariants from fields.

Definition at line 466 of file qgsfields.h.

◆ operator!=()

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

inline

Definition at line 412 of file qgsfields.h.

◆ operator=()

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

Assignment operator.

Definition at line 39 of file qgsfields.cpp.

◆ operator==()

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

Definition at line 221 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 159 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 185 of file qgsfields.cpp.

◆ remove()

void QgsFields::remove ( int fieldIdx )

Removes the field with the given index.

Definition at line 102 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 73 of file qgsfields.cpp.

◆ size()

int QgsFields::size ( ) const

Returns number of items.

Definition at line 139 of file qgsfields.cpp.

◆ toList()

QList< QgsField > QgsFields::toList ( ) const

Utility function to return a list of QgsField instances.

Definition at line 213 of file qgsfields.cpp.

Property Documentation

◆ count

int QgsFields::count

read

Definition at line 50 of file qgsfields.h.

◆ isEmpty

bool QgsFields::isEmpty

read

Definition at line 49 of file qgsfields.h.

◆ names

QStringList QgsFields::names

read

Definition at line 51 of file qgsfields.h.

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

/home/fischer/src/qgis-3.38/src/core/qgsfields.h
/home/fischer/src/qgis-3.38/src/core/qgsfields.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Properties

Detailed Description

Member Typedef Documentation

◆ Field

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() [1/2]

◆ iconForFieldType() [2/2]

◆ indexFromName()

◆ indexOf()

◆ isEmpty()

◆ lookupField()

◆ names()

◆ operator QVariant()

◆ operator!=()

◆ operator=()

◆ operator==()

◆ operator[]() [1/2]

◆ operator[]() [2/2]

◆ remove()

◆ rename()

◆ size()

◆ toList()

Property Documentation

◆ count

◆ isEmpty

◆ names