I am trying to create a list-type field for the active layer using the code below, which is not working.
Is there any other way to create a list-type field and update the list([1,2,3]) as an attribute value to the created area?
layer = iface.activeLayer()
field = 'list_field'
if layer.fields().indexFromName(field) == -1:
fieldz = QgsField(field , QVariant.list)
layer.dataProvider().addAttributes([fieldz])
layer.updateFields()
I could get the same error as you:
Traceback (most recent call last):
File "C:\PROGRA~1\QGIS32~1.0\apps\Python39\lib\code.py", line 90, in runcode
exec(code, self.locals)
File "<input>", line 1, in <module>
File "<string>", line 5, in <module>
AttributeError: type object 'QVariant' has no attribute 'list'
This happened due to the wrong specification of the QVariant type. It should be QVariant.List instead of QVariant.list, see the documentation:
from qgis.core import QgsField, QgsVariantUtils
from PyQt5.QtCore import QVariant
new_field = QgsField("ListField", QVariant.List)
print(QgsVariantUtils.typeToDisplayString(new_field.type())) # List
So, your code can be adjusted as follows:
from qgis.gui import QgisInterface
from qgis.core import QgsField
from PyQt5.QtCore import QVariant
layer = iface.activeLayer()
field = 'list_field'
if layer.fields().indexFromName(field) == -1:
fieldz = QgsField(field , QVariant.List)
layer.dataProvider().addAttributes([fieldz])
layer.updateFields()
However, I would probably proceed in a slightly different manner to create a new field:
from qgis.gui import QgisInterface
from qgis.core import QgsField
from PyQt5.QtCore import QVariant
layer = iface.activeLayer()
field = 'list_field'
if field not in layer.fields().names():
layer_provider = layer.dataProvider()
layer_provider.addAttributes([QgsField(field, QVariant.List)])
layer.updateFields()
Also, keep in mind that you may encounter the following error e.g.:
Layer <LAYER_NAME>: type for field list_field not found
References:
