QGIS API Documentation 3.28.0-Firenze (ed3ad0430f)
Classes | Public Types | Public Member Functions | Static Public Member Functions | List of all members
QgsFields Class Reference

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. More...
 
 QgsFields (const QgsFields &other)
 Copy constructor. More...
 
virtual ~QgsFields ()
 
QgsAttributeList allAttributesList () const
 Utility function to get list of attribute indexes. More...
 
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) More...
 
bool appendExpressionField (const QgsField &field, int originIndex)
 Appends an expression field. The field must have unique name, otherwise it is rejected (returns false) More...
 
QgsField at (int i) const
 Returns the field at particular index (must be in range 0..N-1). More...
 
iterator begin ()
 Returns an STL-style iterator pointing to the first item in the list. More...
 
const_iterator begin () const noexcept
 Returns a const STL-style iterator pointing to the first item in the list. More...
 
void clear ()
 Removes all fields. More...
 
const_iterator constBegin () const noexcept
 Returns a const STL-style iterator pointing to the first item in the list. More...
 
const_iterator constEnd () const noexcept
 Returns a const STL-style iterator pointing to the imaginary item after the last item in the list. More...
 
int count () const
 Returns number of items. More...
 
iterator end ()
 Returns an STL-style iterator pointing to the imaginary item after the last item in the list. More...
 
const_iterator end () const noexcept
 Returns a const STL-style iterator pointing to the imaginary item after the last item in the list. More...
 
bool exists (int i) const
 Returns if a field index is valid. More...
 
void extend (const QgsFields &other)
 Extends with fields from another QgsFields container. More...
 
QgsField field (const QString &name) const
 Returns the field with matching name. More...
 
QgsField field (int fieldIdx) const
 Returns the field at particular index (must be in range 0..N-1). More...
 
FieldOrigin fieldOrigin (int fieldIdx) const
 Returns the field's origin (value from an enumeration). More...
 
int fieldOriginIndex (int fieldIdx) const
 Returns the field's origin index (its meaning is specific to each type of origin). More...
 
QIcon iconForField (int fieldIdx, bool considerOrigin=false) const
 Returns an icon corresponding to a field index, based on the field's type and source. More...
 
int indexFromName (const QString &fieldName) const
 Gets the field index from the field name. More...
 
int indexOf (const QString &fieldName) const
 Gets the field index from the field name. More...
 
bool isEmpty () const
 Checks whether the container is empty. More...
 
int lookupField (const QString &fieldName) const
 Looks up field's index from the field name. More...
 
QStringList names () const
 Returns a list with field names. More...
 
 operator QVariant () const
 Allows direct construction of QVariants from fields. More...
 
bool operator!= (const QgsFields &other) const
 
QgsFieldsoperator= (const QgsFields &other)
 Assignment operator. More...
 
bool operator== (const QgsFields &other) const
 
QgsFieldoperator[] (int i)
 Gets field at particular index (must be in range 0..N-1) More...
 
QgsField operator[] (int i) const
 Gets field at particular index (must be in range 0..N-1) More...
 
void remove (int fieldIdx)
 Removes the field with the given index. More...
 
bool rename (int fieldIdx, const QString &name)
 Renames a name of field. More...
 
int size () const
 Returns number of items. More...
 
QList< QgsFieldtoList () const
 Utility function to return a list of QgsField instances. More...
 

Static Public Member Functions

static QIcon iconForFieldType (QVariant::Type type, QVariant::Type subType=QVariant::Type::Invalid)
 Returns an icon corresponding to a field type. More...
 

Detailed Description

Container of fields for a vector layer.

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

Note
QgsFields objects are implicitly shared.

Definition at line 44 of file qgsfields.h.

Member Typedef Documentation

◆ Field

Member Enumeration Documentation

◆ 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.

Since
QGIS 2.4

Definition at line 376 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
Since
QGIS 2.16

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
Since
QGIS 2.16

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
Since
QGIS 2.16

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
Since
QGIS 2.16

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
Since
QGIS 2.16

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
Since
QGIS 2.16

Definition at line 249 of file qgsfields.cpp.

◆ exists()

bool QgsFields::exists ( int  i) const

Returns if a field index is valid.

Parameters
iIndex 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
fieldIdxthe field index
considerOriginif true the icon will the origin of the field
Since
QGIS 2.14

Definition at line 275 of file qgsfields.cpp.

◆ iconForFieldType()

QIcon QgsFields::iconForFieldType ( QVariant::Type  type,
QVariant::Type  subType = QVariant::Type::Invalid 
)
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 3.16

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
fieldNameThe 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
fieldNameThe 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.
Since
QGIS 3.0

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:

  1. The exact field name taking case sensitivity into account
  2. Looks for the field name by case insensitive comparison
  3. The field alias (case insensitive)
Parameters
fieldNameThe 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.
Since
QGIS 2.4

Definition at line 349 of file qgsfields.cpp.

◆ names()

QStringList QgsFields::names ( ) const

Returns a list with field names.

Since
QGIS 3.0

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 448 of file qgsfields.h.

◆ operator!=()

bool QgsFields::operator!= ( const QgsFields other) const
inline
Since
QGIS 2.6

Definition at line 404 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
Since
QGIS 2.6

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: