Deleting all features of Vector layer using PyQGIS

Question

I am developing a Python plugin for QGIS. In the QGIS map window, certain features of a vector layer are selected and those features are highlighted. Now I need to delete all the existing features from another vector layer without disturbing the current selection in the map window.

Is it possible to delete all the features of a vector layer without selecting them?

Please rephrase your question to indicate where you're getting stuck. Avoid questions that begin with "Is it possible..." as the answer is most likely "Yes". What have you tried so far? — Fezter, Oct 26 '16 at 05:03

score 17 · Accepted Answer · edited Apr 13 '17 at 12:34

17

You could use the following code which is heavily based on the answer from this post: How to delete selected features in QGIS using Python

layer = iface.activeLayer()
with edit(layer):   
    for feat in layer.getFeatures():
        layer.deleteFeature(feat.id())

Edit:

Thanks to @GermánCarrillo, a more efficient method could be to delete all features at once:

layer = iface.activeLayer()
with edit(layer):
    listOfIds = [feat.id() for feat in layer.getFeatures()]
    layer.deleteFeatures( listOfIds )

edited Apr 13 '17 at 12:34

Community

1

answered Oct 26 '16 at 09:46

Joseph

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That works perfectly !! – Sjs Oct 26 '16 at 11:50
@Sjs - Awesome, glad it worked =) – Joseph Oct 26 '16 at 11:50
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You could remove all features at once with layer.deleteFeatures( listOfIds ). – Germán Carrillo Oct 26 '16 at 20:00
1

@GermánCarrillo - That is indeed a much better approach, many thanks ;) – Joseph Nov 07 '16 at 10:08
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For Qgis 3.2 instead of layer.deleteFeatures( listOfIds ) works layer.dataProvider().deleteFeatures( listOfIds ) – Vadym Dec 07 '18 at 19:11

score 10 · Answer 2 · edited Nov 01 '23 at 13:44

10

In QGIS 3 one can use the truncate() method of the QgsVectorDataProvider class.

Removes all features from the layer.

This requires either the FastTruncate or DeleteFeatures capability. Providers with the FastTruncate capability will use an optimised method to truncate the layer.

# referring to the original Vector layer
layer = QgsProject.instance().mapLayersByName("points")[0]
accessing Vector layer provider
provider = source_layer.dataProvider()
deleting all features in the Vector layer
provider.truncate()

edited Nov 01 '23 at 13:44

Taras

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answered May 12 '17 at 11:56

Peter Petrik

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That's a nice new feature :) – Joseph May 12 '17 at 11:59
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It is not work in editing mode – Mustafa Uçar Apr 08 '19 at 09:42

Deleting all features of Vector layer using PyQGIS

2 Answers2

accessing Vector layer provider

deleting all features in the Vector layer

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