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nyalldawsonnyalldawson
committedNov 2, 2016
New class QgsVectorLayerUtils
Contains static helper methods for working with vector layers. Initially only contains a method to test whether a value exists within a layer's attributes.
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ltr-3_40final-3_0_0
1 parent 3e40f80 commit b7d0fd6

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‎python/core/core.sip

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%Include qgsvectorlayerimport.sip
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%Include qgsvectorlayerjoinbuffer.sip
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%Include qgsvectorlayerundocommand.sip
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%Include qgsvectorlayerutils.sip
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%Include qgsvectorsimplifymethod.sip
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%Include qgscachedfeatureiterator.sip

‎python/core/qgsvectorlayerutils.sip

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/** \ingroup core
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* \class QgsVectorLayerUtils
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* \brief Contains utility methods for working with QgsVectorLayers.
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*
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* \note Added in version 3.0
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*/
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class QgsVectorLayerUtils
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{
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%TypeHeaderCode
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#include <qgsvectorlayerutils.h>
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%End
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public:
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/**
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* Returns true if the specified value already exists within a field. This method can be used to test for uniqueness
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* of values inside a layer's attributes. An optional list of ignored feature IDs can be provided, if so, any features
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* with IDs within this list are ignored when testing for existance of the value.
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*/
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static bool valueExists( const QgsVectorLayer* layer, int fieldIndex, const QVariant& value, const QgsFeatureIds& ignoreIds = QgsFeatureIds() );
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};

‎src/core/CMakeLists.txt

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@@ -230,6 +230,7 @@ SET(QGIS_CORE_SRCS
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qgsvectorlayerlabelprovider.cpp
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qgsvectorlayerrenderer.cpp
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qgsvectorlayerundocommand.cpp
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qgsvectorlayerutils.cpp
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qgsvectorsimplifymethod.cpp
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qgsvirtuallayerdefinition.cpp
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qgsvirtuallayerdefinitionutils.cpp
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qgsvectorlayerlabelprovider.h
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qgsvectorlayerrenderer.h
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qgsvectorlayerundocommand.h
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qgsvectorlayerutils.h
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qgsvectorsimplifymethod.h
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qgsmapthemecollection.h
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qgsxmlutils.h

‎src/core/qgsvectorlayer.h

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* Provider to display vector data in a GRASS GIS layer.
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*
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* TODO QGIS3: Remove virtual from non-inherited methods (like isModified)
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* @see QgsVectorLayerUtils()
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*/
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‎src/core/qgsvectorlayerutils.cpp

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/***************************************************************************
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qgsvectorlayerutils.cpp
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-----------------------
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Date : October 2016
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Copyright : (C) 2016 by Nyall Dawson
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Email : nyall dot dawson at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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#include "qgsvectorlayerutils.h"
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bool QgsVectorLayerUtils::valueExists( const QgsVectorLayer* layer, int fieldIndex, const QVariant& value, const QgsFeatureIds& ignoreIds )
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{
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if ( !layer )
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return false;
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if ( fieldIndex < 0 || fieldIndex >= layer->fields().count() )
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return false;
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QString fieldName = layer->fields().at( fieldIndex ).name();
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// build up an optimised feature request
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QgsFeatureRequest request;
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request.setSubsetOfAttributes( QgsAttributeList() );
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request.setFlags( QgsFeatureRequest::NoGeometry );
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// at most we need to check ignoreIds.size() + 1 - the feature not in ignoreIds is the one we're interested in
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int limit = ignoreIds.size() + 1;
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request.setLimit( limit );
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request.setFilterExpression( QStringLiteral( "%1=%2" ).arg( QgsExpression::quotedColumnRef( fieldName ),
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QgsExpression::quotedValue( value ) ) );
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QgsFeature feat;
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QgsFeatureIterator it = layer->getFeatures( request );
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while ( it.nextFeature( feat ) )
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{
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if ( ignoreIds.contains( feat.id() ) )
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continue;
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return true;
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}
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return false;
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}

‎src/core/qgsvectorlayerutils.h

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/***************************************************************************
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qgsvectorlayerutils.h
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---------------------
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Date : October 2016
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Copyright : (C) 2016 by Nyall Dawson
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Email : nyall dot dawson at gmail dot com
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***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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#ifndef QGSVECTORLAYERUTILS_H
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#define QGSVECTORLAYERUTILS_H
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#include "qgsvectorlayer.h"
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/** \ingroup core
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* \class QgsVectorLayerUtils
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* \brief Contains utility methods for working with QgsVectorLayers.
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*
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* \note Added in version 3.0
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*/
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class CORE_EXPORT QgsVectorLayerUtils
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{
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public:
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/**
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* Returns true if the specified value already exists within a field. This method can be used to test for uniqueness
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* of values inside a layer's attributes. An optional list of ignored feature IDs can be provided, if so, any features
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* with IDs within this list are ignored when testing for existance of the value.
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*/
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static bool valueExists( const QgsVectorLayer* layer, int fieldIndex, const QVariant& value, const QgsFeatureIds& ignoreIds = QgsFeatureIds() );
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};
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#endif // QGSVECTORLAYERUTILS_H

‎tests/src/python/CMakeLists.txt

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@@ -111,6 +111,7 @@ ADD_PYTHON_TEST(PyQgsVectorColorRamp test_qgsvectorcolorramp.py)
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ADD_PYTHON_TEST(PyQgsVectorFileWriter test_qgsvectorfilewriter.py)
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ADD_PYTHON_TEST(PyQgsVectorLayer test_qgsvectorlayer.py)
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ADD_PYTHON_TEST(PyQgsVectorLayerEditBuffer test_qgsvectorlayereditbuffer.py)
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ADD_PYTHON_TEST(PyQgsVectorLayerUtils test_qgsvectorlayerutils.py)
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ADD_PYTHON_TEST(PyQgsZonalStatistics test_qgszonalstatistics.py)
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ADD_PYTHON_TEST(PyQgsMapLayerRegistry test_qgsmaplayerregistry.py)
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ADD_PYTHON_TEST(PyQgsVirtualLayerProvider test_provider_virtual.py)

‎tests/src/python/test_qgsvectorlayerutils.py

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# -*- coding: utf-8 -*-
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"""QGIS Unit tests for QgsVectorLayerUtils.
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.. note:: This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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"""
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__author__ = 'Nyall Dawson'
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__date__ = '25/10/2016'
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__copyright__ = 'Copyright 2016, The QGIS Project'
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# This will get replaced with a git SHA1 when you do a git archive
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__revision__ = '$Format:%H$'
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import qgis # NOQA
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import os
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from qgis.PyQt.QtCore import QVariant
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from qgis.core import (QgsVectorLayer,
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QgsVectorLayerUtils,
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QgsField,
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QgsFields,
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QgsFeature
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)
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from qgis.testing import start_app, unittest
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from utilities import unitTestDataPath
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start_app()
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def createLayerWithOnePoint():
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layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer",
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"addfeat", "memory")
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pr = layer.dataProvider()
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f = QgsFeature()
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f.setAttributes(["test", 123])
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assert pr.addFeatures([f])
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assert layer.pendingFeatureCount() == 1
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return layer
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class TestQgsVectorLayerUtils(unittest.TestCase):
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def test_value_exists(self):
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layer = createLayerWithOnePoint()
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# add some more features
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f1 = QgsFeature(2)
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f1.setAttributes(["test1", 124])
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f2 = QgsFeature(3)
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f2.setAttributes(["test2", 125])
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f3 = QgsFeature(4)
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f3.setAttributes(["test3", 126])
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f4 = QgsFeature(5)
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f4.setAttributes(["test4", 127])
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layer.dataProvider().addFeatures([f1, f2, f3, f4])
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 0, 'test'))
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 0, 'test1'))
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 0, 'test4'))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 0, 'not present!'))
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 1, 123))
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 1, 124))
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 1, 127))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 1, 99))
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# no layer
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self.assertFalse(QgsVectorLayerUtils.valueExists(None, 1, 123))
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# bad field indexes
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, -1, 'test'))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 100, 'test'))
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# with ignore list
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 0, 'test1', [3, 4, 5]))
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 0, 'test1', [999999]))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 0, 'test1', [2]))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 0, 'test1', [99999, 2]))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 0, 'test1', [3, 4, 5, 2]))
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 1, 125, [2, 4, 5]))
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self.assertTrue(QgsVectorLayerUtils.valueExists(layer, 1, 125, [999999]))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 1, 125, [3]))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 1, 125, [99999, 3]))
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self.assertFalse(QgsVectorLayerUtils.valueExists(layer, 1, 125, [2, 4, 5, 3]))
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if __name__ == '__main__':
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unittest.main()

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