Subgroup: Feature
Class: QgsFeatureSource¶
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class
qgis.core.
QgsFeatureSource
¶ Bases:
sip.wrapper
An interface for objects which provide features via a getFeatures method.
New in version 3.0: Methods
allFeatureIds
Returns a list of all feature IDs for features present in the source. featureCount
Returns the number of features contained in the source, or -1 if the feature count is unknown. fields
Returns the fields associated with features in the source. getFeatures
Returns an iterator for the features in the source. materialize
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.maximumValue
Returns the maximum value for an attribute column or an invalid variant in case of error. minimumValue
Returns the minimum value for an attribute column or an invalid variant in case of error. sourceCrs
Returns the coordinate reference system for features in the source. sourceExtent
Returns the extent of all geometries from the source. sourceName
Returns a friendly display name for the source. uniqueValues
Returns the set of unique values contained within the specified fieldIndex
from this source.wkbType
Returns the geometry type for features returned by this source. Signals
Attributes
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allFeatureIds
(self) → object¶ Returns a list of all feature IDs for features present in the source.
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featureCount
(self) → int¶ Returns the number of features contained in the source, or -1 if the feature count is unknown.
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fields
(self) → QgsFields¶ Returns the fields associated with features in the source.
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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.
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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.
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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
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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
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sourceCrs
(self) → QgsCoordinateReferenceSystem¶ Returns the coordinate reference system for features in the source.
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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.
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sourceName
(self) → str¶ Returns a friendly display name for the source. The returned value can be an empty string.
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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
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wkbType
(self) → QgsWkbTypes.Type¶ Returns the geometry type for features returned by this source.
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