Class: QgsFeatureSource¶
-
class
qgis.core.
QgsFeatureSource
¶ Bases:
sip.wrapper
An interface for objects which provide features via a getFeatures method.
Methods
Returns a list of all feature IDs for features present in the source.
Returns the number of features contained in the source, or -1 if the feature count is unknown.
Returns the fields associated with features in the source.
Returns an iterator for the features in the source.
Determines if there are any features available in the source.
Materializes a
request
(query) made against this feature source, by running it over the source and returning a new memory based vector layer containing the result.Returns the maximum value for an attribute column or an invalid variant in case of error.
Returns the minimum value for an attribute column or an invalid variant in case of error.
Returns the coordinate reference system for features in the source.
Returns the extent of all geometries from the source.
Returns a friendly display name for the source.
Returns the set of unique values contained within the specified
fieldIndex
from this source.Returns the geometry type for features returned by this source.
Attributes
-
class
FeatureAvailability
¶ Bases:
int
-
FeaturesAvailable
= 1¶
-
FeaturesMaybeAvailable
= 2¶
-
NoFeaturesAvailable
= 0¶
-
allFeatureIds
(self) → object¶ Returns a list of all feature IDs for features present in the source.
- Return type
object
-
featureCount
(self) → int¶ Returns the number of features contained in the source, or -1 if the feature count is unknown.
- Return type
int
-
fields
(self) → QgsFields¶ Returns the fields associated with features in the source.
- Return type
-
getFeatures
(self, request: QgsFeatureRequest = QgsFeatureRequest()) → QgsFeatureIterator¶ Returns an iterator for the features in the source. An optional
request
can be used to optimise the returned iterator, eg by restricting the returned attributes or geometry.- Parameters
request (
QgsFeatureRequest
= QgsFeatureRequest()) –- Return type
-
hasFeatures
(self) → QgsFeatureSource.FeatureAvailability¶ Determines if there are any features available in the source.
New in version 3.2.
- Return type
-
materialize
(self, request: QgsFeatureRequest, feedback: QgsFeedback = None) → QgsVectorLayer¶ Materializes a
request
(query) made against this feature source, by running it over the source and returning a new memory based vector layer containing the result. All settings from featurerequest
will be honored.If a subset of attributes has been set for the request, then only those selected fields will be present in the output layer.
The CRS for the output layer will match the input layer, unless QgsFeatureRequest.setDestinationCrs() has been called with a valid
QgsCoordinateReferenceSystem
. In this case the output layer will match the QgsFeatureRequest.destinationCrs() CRS.The returned layer WKB type will match wkbType(), unless the QgsFeatureRequest.NoGeometry flag is set on the
request
. In that case the returned layer will not be a spatial layer.An optional
feedback
argument can be used to cancel the materialization before it has fully completed.The returned value is a new instance and the caller takes responsibility for its ownership.
New in version 3.0.
- Parameters
request (QgsFeatureRequest) –
feedback (
QgsFeedback
= None) –
- Return type
-
maximumValue
(self, fieldIndex: int) → Any¶ Returns the maximum value for an attribute column or an invalid variant in case of error. The base class implementation uses a non-optimised approach of looping through all features in the source.
See also
See also
- Parameters
fieldIndex (int) –
- Return type
Any
-
minimumValue
(self, fieldIndex: int) → Any¶ Returns the minimum value for an attribute column or an invalid variant in case of error. The base class implementation uses a non-optimised approach of looping through all features in the source.
See also
See also
- Parameters
fieldIndex (int) –
- Return type
Any
-
sourceCrs
(self) → QgsCoordinateReferenceSystem¶ Returns the coordinate reference system for features in the source.
- Return type
-
sourceExtent
(self) → QgsRectangle¶ Returns the extent of all geometries from the source. The base class implementation uses a non-optimised approach of looping through all features in the source.
- Return type
-
sourceName
(self) → str¶ Returns a friendly display name for the source. The returned value can be an empty string.
- Return type
str
-
uniqueValues
(self, fieldIndex: int, limit: int = -1) → object¶ Returns the set of unique values contained within the specified
fieldIndex
from this source. If specified, thelimit
option can be used to limit the number of returned values. The base class implementation uses a non-optimised approach of looping through all features in the source.See also
See also
- Parameters
fieldIndex (int) –
limit (int = -1) –
- Return type
object
-
wkbType
(self) → QgsWkbTypes.Type¶ Returns the geometry type for features returned by this source.
- Return type
-
class