Using the advanced filter of an attribute table from python

Question

I have created a script which opens the attribute table in QGIS and I would like to use the advanced filter (expression). I want to create the expression from python and then show the result in the attribute table.

Code:

request = QgsFeatureRequest().setFilterExpression( u'"STATUS" = \'OK\'' )
self.attDialog = self.iface.showAttributeTable(self.layer)
self.attDialog.findChild(QAction,'mActionAdvancedFilter').trigger()

Do you know how could I do that?

The expected result should be something like this:

Nop. If you want to try it in the console, remove the 'self.' and assign layer = iface.activeLayer() — p374, Feb 17 '20 at 14:18
it does open a modal expression builder dialog when I try it on the console, confirm? (appologize my quick shot answer below...) — Jochen Schwarze, Feb 17 '20 at 14:55
Yup @JochenSchwarze Ideally I would like to pass the expression via python and get the result as shown in the image. — p374, Feb 17 '20 at 14:56
Do you need to filter features in attribute table without filtering in map canvas, as "Advanced Filter (Expression)" does, right? — Kadir Şahbaz, Feb 17 '20 at 16:07

Kadir Şahbaz · Accepted Answer · 2020-02-17T18:59:57.833

QGIS Python Editor version:

from qgis.PyQt.QtGui import *

layer = iface.activeLayer()

attDialog = iface.showAttributeTable(layer)

# firstly, you need get some widgets
mFilterButton = attDialog.findChild(QToolButton,'mFilterButton')
mActionAdvancedFilter = attDialog.findChild(QAction,'mActionAdvancedFilter')
mFilterQuery = attDialog.findChild(QLineEdit,'mFilterQuery')
mActionApplyFilter = attDialog.findChild(QAction,'mActionApplyFilter')

# set checked Advanced Filter (Expression)
mFilterButton.setDefaultAction(mActionAdvancedFilter)

# You can use string version of request
request = u'"STATUS" = \'OK\'' 
# add query string to the text box
mFilterQuery.setText(request)
mFilterQuery.setVisible(True)

# apply query
mActionApplyFilter.trigger()

Plugin version:

self.attDialog = self.iface.showAttributeTable(self.layer)

mFilterButton = self.attDialog.findChild(QToolButton,'mFilterButton')
mActionAdvancedFilter = self.attDialog.findChild(QAction,'mActionAdvancedFilter')
mFilterQuery = self.attDialog.findChild(QLineEdit,'mFilterQuery')
mActionApplyFilter = self.attDialog.findChild(QAction,'mActionApplyFilter')

...
...

Amazing! This was exactly what I was looking for! Thank you very much! — p374, Feb 17 '20 at 22:21

Jochen Schwarze · Answer 2 · 2020-02-17T14:38:03.653

5

Either

You can pass the expression string directly to the selectByExpression() method of your QgsVectorLayer instance like this:

self.layer.selectByExpression('"STATUS" = \'OK\'')

u'...' is not needed since everything is unicode in Python 3.

Then you show the attribute table as shown above

self.attDialog = self.iface.showAttributeTable(self.layer)

and set its behaviour to only show the selected features

self.attDialog.findChild(QAction,'mActionSelectedFilter').trigger()

cp. PyQGIS Attribute table show selected features

Or

If working with selections is unwanted one may apply a filter to the layer by

self.layer.setSubsetString(''"STATUS" = \'OK\''')

and open the attribute table.

Delete the filter by

self.layer.setSubsetString('')

Note that subset strings are plain sql.

cp. https://qgis.org/api/classQgsVectorLayer.html#aba0ee124dcf2d037f3af53d99866c01c

edited Feb 17 '20 at 14:38

answered Feb 17 '20 at 14:18

Jochen Schwarze

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I don't want to use 'mActionSelectedFilter' because if I select one of the selected features the rest of them will disappear from the attribute table. – p374 Feb 17 '20 at 14:21
got you. see my edit, possibly applying a filter is what you are looking for. – Jochen Schwarze Feb 17 '20 at 14:38
1

Your subsetString thing works fine but only if the layer is NOT in edit mode! – p374 Feb 17 '20 at 15:07

Using the advanced filter of an attribute table from python

2 Answers2