Using the python console, I am trying to copy values from a virtual field into another non-virtual field. Both fields are integer types but I get NULL in the non-virtual field. I followed the answer in this post: Is it possible to programmatically add calculated fields?
The following code works if both fields are non-virtual but doesn't work if copying from a virtual field. Here is the code:
from PyQt4.QtCore import QVariantfrom qgis.core import QgsField, QgsExpression, QgsFeaturevl = QgsVectorLayer("C:\Users\Me\Desktop\Test\\Layer.shp", "Layer", "ogr")vl.startEditing()myField = QgsField( 'Field_1', QVariant.Int ) # Field_1 is the non-virtual fieldvl.addAttribute( myField )idx = vl.fieldNameIndex( 'Field_1' )e = QgsExpression( 'Field_2' ) # Field_2 is the virtual fielde.prepare( vl.pendingFields() )for f in vl.getFeatures(): f[idx] = e.evaluate( f ) vl.updateFeature( f )vl.commitChanges()Any help is greatly appreciated!
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The following code works if both fields are non-virtual but doesn't work if copying from a virtual field. Here is the code:
from PyQt4.QtCore import QVariantfrom qgis.core import QgsField, QgsExpression, QgsFeaturevl = QgsVectorLayer("C:\Users\Me\Desktop\Test\\Layer.shp", "Layer", "ogr")vl.startEditing()myField = QgsField( 'Field_1', QVariant.Int ) # Field_1 is the non-virtual fieldvl.addAttribute( myField )idx = vl.fieldNameIndex( 'Field_1' )e = QgsExpression( 'Field_2' ) # Field_2 is the virtual fielde.prepare( vl.pendingFields() )for f in vl.getFeatures(): f[idx] = e.evaluate( f ) vl.updateFeature( f )vl.commitChanges()Any help is greatly appreciated!
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