Add a module for editting a layer's field (computing area)

services_scripts/add_new_field.py

@@ -5,10 +5,10 @@ from qgis.PyQt.QtCore import QVariant
 layer = QgsVectorLayer(
   'C:/Users/a_adli/PycharmProjects/'
   'hydroquebec_archetype_gispy/data/'
-  'output_data/multi_to_single/multi_to_single.shp', "your_layer", "ogr")
+  'output_data/multi_to_single/multi_to_single.shp', 'your_layer', 'ogr')
 functionalities = layer.dataProvider().capabilities()
 
 if functionalities & QgsVectorDataProvider.AddAttributes:
-    new_field = QgsField("Area", QVariant.Double) 
+    new_field = QgsField("Area", QVariant.Double)
     layer.dataProvider().addAttributes([new_field])
     layer.updateFields()

services_scripts/edit_field.py

@@ -0,0 +1,26 @@
+"""
+This code is to show how to edit a layer's field. In this example,
+the area of each record is calculated and will be assigned to the
+field (here 'Area')
+"""
+from qgis.core import QgsVectorLayer, QgsExpressionContext, QgsExpressionContextUtils
+
+
+layer = QgsVectorLayer(
+  'C:/Users/a_adli/PycharmProjects/'
+  'hydroquebec_archetype_gispy/data/'
+  'output_data/multi_to_single/multi_to_single.shp', 'your_layer', 'ogr')
+
+layer.startEditing()
+idx = layer.fields().indexFromName('Area')
+
+
+context = QgsExpressionContext()
+context.appendScopes(QgsExpressionContextUtils.globalProjectLayerScopes(layer))
+
+for feature in layer.getFeatures():
+    area = feature.geometry().area()
+    feature[idx] = area
+    layer.updateFeature(feature)
+
+layer.commitChanges()