Class: QgsAbstractFeatureIterator

class qgis.core.QgsAbstractFeatureIterator(request: QgsFeatureRequest)

Bases: sip.wrapper

base class constructor - stores the iteration parameters

QgsAbstractFeatureIterator(QgsAbstractFeatureIterator)

Internal feature iterator to be implemented within data providers

Parameters

request

class CompileStatus

Bases: int

Compiled = 2
NoCompilation = 0
PartiallyCompiled = 1
close(self) → bool

end of iterating: free the resources / lock

Return type

bool

compileFailed(self) → bool

Indicator if there was an error when sending the compiled query to the server. This indicates that there is something wrong with the expression compiler.

New in version 3.2.

Return type

bool

compileStatus(self) → QgsAbstractFeatureIterator.CompileStatus

Returns the status of expression compilation for filter expression requests.

New in version 2.16.

Return type

QgsAbstractFeatureIterator.CompileStatus

deref(self)

Remove reference, delete if refs == 0

fetchFeature(self, f: QgsFeature) → bool

If you write a feature iterator for your provider, this is the method you need to implement!!

Parameters

f (QgsFeature) – The feature to write to

Return type

bool

Returns

True if a feature was written to f

filterRectToSourceCrs(self, transform: QgsCoordinateTransform) → QgsRectangle

Returns a rectangle representing the original request’s QgsFeatureRequest.filterRect() If transform is a valid coordinate transform, the return rectangle will represent the requested filterRect() transformed to the source’s coordinate reference system. Iterators should call this method and use the returned rectangle for filtering features to ensure that any QgsFeatureRequest.destinationCrs() set on the request is respected. Will throw a QgsCsException if the rect cannot be transformed from the destination CRS.

New in version 3.0.

Parameters

transform (QgsCoordinateTransform) –

Return type

QgsRectangle

geometryToDestinationCrs(self, feature: QgsFeature, transform: QgsCoordinateTransform)

Transforms feature’s geometry according to the specified coordinate transform. If feature has no geometry or transform is invalid then calling this method has no effect and will be shortcut. Iterators should call this method before returning features to ensure that any QgsFeatureRequest.destinationCrs() set on the request is respected.

New in version 3.0.

Parameters
isValid(self) → bool

Returns if this iterator is valid. An invalid feature iterator is not able to provide a reliable source for data. If an iterator is invalid, either give up or try to send the request again (preferably after a timeout to give the system some time to stay responsive).

If you want to check if the iterator successfully completed, better use QgsFeatureIterator.isClosed()

New in version 3.0.

Return type

bool

nextFeature(self, f: QgsFeature) → bool

fetch next feature, return True on success

Parameters

f (QgsFeature) –

Return type

bool

nextFeatureFilterExpression(self, f: QgsFeature) → bool

By default, the iterator will fetch all features and check if the feature matches the expression. If you have a more sophisticated metodology (SQL request for the features…) and you check for the expression in your fetchFeature method, you can just redirect this call to fetchFeature so the default check will be omitted.

Parameters

f (QgsFeature) – The feature to write to

Return type

bool

Returns

True if a feature was written to f

nextFeatureFilterFids(self, f: QgsFeature) → bool

By default, the iterator will fetch all features and check if the id is in the request. If you have a more sophisticated metodology (SQL request for the features…) and you are sure, that any feature you return from fetchFeature will match if the request was FilterFids you can just redirect this call to fetchFeature so the default check will be omitted.

Parameters

f (QgsFeature) – The feature to write to

Return type

bool

Returns

True if a feature was written to f

prepareSimplification(self, simplifyMethod: QgsSimplifyMethod) → bool

Setup the simplification of geometries to fetch using the specified simplify method

Parameters

simplifyMethod (QgsSimplifyMethod) –

Return type

bool

ref(self)

Add reference

rewind(self) → bool

reset the iterator to the starting position

Return type

bool