Class: QgsFields¶

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.

Enums

FieldOrigin

Field origin.

Methods

`allAttributesList`	Utility function to get list of attribute indexes
`append`	Appends a field.
`appendExpressionField`	Appends an expression field.
`at`	Returns the field at particular index (must be in range 0..N-1).
`clear`	Removes all fields
`count`	Returns number of items
`exists`	Returns if a field index is valid
`extend`	Extends with fields from another `QgsFields` container
`field`	Returns the field at particular index (must be in range 0..N-1).
`fieldOrigin`	Returns the field's origin (value from an enumeration).
`fieldOriginIndex`	Returns the field's origin index (its meaning is specific to each type of origin).
`iconForField`	Returns an icon corresponding to a field index, based on the field's type and source
`indexFromName`	Gets the field index from the field name.
`indexOf`	Gets the field index from the field name.
`isEmpty`	Checks whether the container is empty
`lookupField`	Looks up field's index from the field name.
`names`	Returns a list with field names
`remove`	Removes the field with the given index.
`rename`	Renames a name of field.
`size`	Returns number of items
`toList`	Utility function to return a list of `QgsField` instances

Static Methods

iconForFieldType

Returns an icon corresponding to a field type

class qgis.core.QgsFields[source]¶

Bases: object

__init__(): Constructor for an empty field container

__init__(other: QgsFields)

Parameters:: other (QgsFields)

__init__(fields: Any)

Construct QgsFields from a list of fields.

Added in version 3.40.

Parameters:: fields (Any)

class FieldOrigin(*values)¶

Bases: IntEnum

Field origin.

Note

Prior to QGIS 3.38 this was available as QgsFields.FieldOrigin

Added in version 3.38.

Unknown: The field origin has not been specified

Available as QgsFields.OriginUnknown in older QGIS releases.
Provider: Field originates from the underlying data provider of the vector layer

Available as QgsFields.OriginProvider in older QGIS releases.
Join: Field originates from a joined layer

Available as QgsFields.OriginJoin in older QGIS releases.
Edit: Field has been temporarily added in editing mode

Available as QgsFields.OriginEdit in older QGIS releases.
Expression: Field is calculated from an expression

Available as QgsFields.OriginExpression in older QGIS releases.

allAttributesList(self) → List[int][source]¶

Utility function to get list of attribute indexes

Return type:: List[int]

append(self, field: QgsField, origin: Qgis.FieldOrigin = Qgis.FieldOrigin.Provider, originIndex: int = -1) → bool[source]¶

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

Parameters:

field (QgsField)
origin (Qgis.FieldOrigin = Qgis.FieldOrigin.Provider)
originIndex (int = -1)

Return type:

bool

append(self, fields: Any, origin: Qgis.FieldOrigin = Qgis.FieldOrigin.Provider) → bool[source]

Appends a list of fields.

The fields must have unique names, otherwise it is rejected (returns False).

Added in version 3.40.

Parameters:

fields (Any)
origin (Qgis.FieldOrigin = Qgis.FieldOrigin.Provider)

Return type:

bool

append(self, fields: QgsFields) → bool[source]

Appends another set of fields to these fields.

The fields must have unique names, otherwise it is rejected (returns False).

Added in version 3.40.

Parameters:: fields (QgsFields)
Return type:: bool

appendExpressionField(self, field: QgsField, originIndex: int) → bool[source]¶

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

Parameters:

field (QgsField)
originIndex (int)

Return type:

bool

at(self, i: int) → QgsField[source]¶

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

Raises:: KeyError – if no field exists at the specified index
Parameters:: i (int)
Return type:: QgsField

clear(self)[source]¶: Removes all fields

count(self) → int[source]¶

Returns number of items

Return type:: int

exists(self, i: int) → bool[source]¶

Returns if a field index is valid

Parameters:: i (int) – Index of the field which needs to be checked
Return type:: bool
Returns:: True if the field exists

extend(self, other: QgsFields)[source]¶

Extends with fields from another QgsFields container

Parameters:: other (QgsFields)

field(self, fieldIdx: int) → QgsField[source]¶

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

Raises:: KeyError – if no field exists at the specified index
Parameters:: fieldIdx (int)
Return type:: QgsField

field(self, name: str | None) → QgsField[source]

Returns the field with matching name.

Raises:: KeyError – if no matching field was found.
Parameters:: name (Optional[str])
Return type:: QgsField

fieldOrigin(self, fieldIdx: int) → Qgis.FieldOrigin[source]¶

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

Raises:: KeyError – if no field exists at the specified index
Parameters:: fieldIdx (int)
Return type:: Qgis.FieldOrigin

fieldOriginIndex(self, fieldIdx: int) → int[source]¶

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

Raises:: KeyError – if no field exists at the specified index
Parameters:: fieldIdx (int)
Return type:: int

iconForField(self, fieldIdx: int, considerOrigin: bool = False) → QIcon[source]¶

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

Parameters:

fieldIdx (int) – the field index
considerOrigin (bool = False) – if True the icon will the origin of the field

Raises:

KeyError – if no field exists at the specified index

Return type:

QIcon

static iconForFieldType(type: QMetaType.Type, subType: QMetaType.Type = QMetaType.Type.UnknownType, typeString: str | None = '') → QIcon[source]¶

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.

Added in version 3.16.

Parameters:

type (QMetaType.Type)
subType (QMetaType.Type = QMetaType.Type.UnknownType)
typeString (Optional[str] = '')

Return type:

QIcon

static iconForFieldType(type: QVariant.Type, subType: QVariant.Type, typeString: str | None = '') → QIcon[source]

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.

Added in version 3.16.

Deprecated since version 3.38: Use the method with a QMetaType.Type argument instead.

Parameters:

type (QVariant.Type)
subType (QVariant.Type)
typeString (Optional[str] = '')

Return type:

QIcon

indexFromName(self, fieldName: str | None) → int[source]¶

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 (Optional[str]) – The name of the field.
Return type:: int
Returns:: The field index if found or -1 in case it cannot be found.