Python QgsFeature.fields方法代码示例

# 需要导入模块: from qgis.core import QgsFeature [as 别名]
# 或者: from qgis.core.QgsFeature import fields [as 别名]
    def testEditGeoJsonAddFieldAndThenAddFeatures(self):
        """ Test bugfix of https://issues.qgis.org/issues/18596 (adding a new field)"""

        datasource = os.path.join(self.basetestpath, 'testEditGeoJsonAddField.json')
        with open(datasource, 'wt') as f:
            f.write("""{
"type": "FeatureCollection",
"features": [
{ "type": "Feature", "properties": { "x": 1 }, "geometry": { "type": "Point", "coordinates": [ 0, 0 ] } } ] }""")

        vl = QgsVectorLayer(datasource, 'test', 'ogr')
        self.assertTrue(vl.isValid())
        self.assertTrue(vl.startEditing())
        self.assertTrue(vl.addAttribute(QgsField('strfield', QVariant.String)))
        self.assertTrue(vl.commitChanges())
        self.assertEqual(len(vl.dataProvider().fields()), 1 + 1)
        self.assertEqual([f.name() for f in vl.dataProvider().fields()], ['x', 'strfield'])

        f = QgsFeature()
        self.assertTrue(vl.getFeatures(QgsFeatureRequest()).nextFeature(f))
        self.assertIsNone(f['strfield'])
        self.assertEqual([field.name() for field in f.fields()], ['x', 'strfield'])

        self.assertTrue(vl.startEditing())
        vl.changeAttributeValue(f.id(), 1, 'x')
        self.assertTrue(vl.commitChanges())
        f = QgsFeature()
        self.assertTrue(vl.getFeatures(QgsFeatureRequest()).nextFeature(f))
        self.assertEqual(f['strfield'], 'x')
        self.assertEqual([field.name() for field in f.fields()], ['x', 'strfield'])

        # Completely reload file
        vl = QgsVectorLayer(datasource, 'test', 'ogr')
        self.assertEqual(len(vl.fields()), 2)

# 需要导入模块: from qgis.core import QgsFeature [as 别名]
# 或者: from qgis.core.QgsFeature import fields [as 别名]
    def addFeatures(self, flist, flags=None):
        added = False
        f_added = []
        for f in flist:
            if f.hasGeometry() and (f.geometry().wkbType() != self.wkbType()):
                return added, f_added

        for f in flist:
            _f = QgsFeature(self.fields())
            _f.setGeometry(f.geometry())
            attrs = [None for i in range(_f.fields().count())]
            for i in range(min(len(attrs), len(f.attributes()))):
                attrs[i] = f.attributes()[i]
            _f.setAttributes(attrs)
            _f.setId(self.next_feature_id)
            self._features[self.next_feature_id] = _f
            self.next_feature_id += 1
            added = True
            f_added.append(_f)

            if self._spatialindex is not None:
                self._spatialindex.insertFeature(_f)

        if len(f_added):
            self.clearMinMaxCache()
            self.updateExtents()

        return added, f_added

# 需要导入模块: from qgis.core import QgsFeature [as 别名]
# 或者: from qgis.core.QgsFeature import fields [as 别名]
    def layerData(self, layer, request={}, offset=0):
        # Retrieve the data for a layer
        first = True
        data = {}
        fields = []
        fieldTypes = []
        fr = QgsFeatureRequest()
        if request:
            if 'exact' in request and request['exact']:
                fr.setFlags(QgsFeatureRequest.ExactIntersect)
            if 'nogeom' in request and request['nogeom']:
                fr.setFlags(QgsFeatureRequest.NoGeometry)
            if 'fid' in request:
                fr.setFilterFid(request['fid'])
            elif 'extents' in request:
                fr.setFilterRect(QgsRectangle(*request['extents']))
            if 'attributes' in request:
                fr.setSubsetOfAttributes(request['attributes'])

        # IMPORTANT - we do not use `for f in layer.getFeatures(fr):` as we need
        # to verify that existing attributes and geometry are correctly cleared
        # from the feature when calling nextFeature()
        it = layer.getFeatures(fr)
        f = QgsFeature()
        while it.nextFeature(f):
            if first:
                first = False
                for field in f.fields():
                    fields.append(str(field.name()))
                    fieldTypes.append(str(field.typeName()))
            if sys.version_info.major == 2:
                fielddata = dict((name, str(f[name])) for name in fields)
            else:
                fielddata = dict((name, str(f[name])) for name in fields)
            g = f.geometry()
            if not g.isEmpty():
                fielddata[geomkey] = str(g.exportToWkt())
            else:
                fielddata[geomkey] = "None"

            fielddata[fidkey] = f.id()
            id = fielddata[fields[0]]
            description = fielddata[fields[1]]
            fielddata['id'] = id
            fielddata['description'] = description
            data[f.id() + offset] = fielddata

        if 'id' not in fields:
            fields.insert(0, 'id')
        if 'description' not in fields:
            fields.insert(1, 'description')
        fields.append(fidkey)
        fields.append(geomkey)
        return fields, fieldTypes, data

# 需要导入模块: from qgis.core import QgsFeature [as 别名]
# 或者: from qgis.core.QgsFeature import fields [as 别名]
 def numericFields(self, layer):
   # get attributes of a sample feature and create numeric field name list
   numeric_fields = []
   f = QgsFeature()
   layer.getFeatures().nextFeature(f)
   for field in f.fields():
     isNumeric = False
     try:
       float(f.attribute(field.name()))
       isNumeric = True
     except ValueError:
       pass
     if isNumeric:
       numeric_fields.append(field.name())
   return numeric_fields

# 需要导入模块: from qgis.core import QgsFeature [as 别名]
# 或者: from qgis.core.QgsFeature import fields [as 别名]
    def addNewFeature(self, form, geometry):
        """
        Add a new new feature to the given layer
        """
        layer = form.QGISLayer
        fields = layer.pendingFields()

        feature = QgsFeature(fields)
        roam.utils.log(feature.fields().toList())
        feature.setGeometry(geometry)

        for indx in xrange(fields.count()):
            feature[indx] = layer.dataProvider().defaultValue(indx)

        self.openForm(form, feature)

# 需要导入模块: from qgis.core import QgsFeature [as 别名]
# 或者: from qgis.core.QgsFeature import fields [as 别名]
    def testCreateFeature(self):
        """ test creating a feature respecting defaults and constraints """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")
        # add a bunch of features
        f = QgsFeature()
        f.setAttributes(["test", 123, 1.0])
        f1 = QgsFeature(2)
        f1.setAttributes(["test_1", 124, 1.1])
        f2 = QgsFeature(3)
        f2.setAttributes(["test_2", 125, 2.4])
        f3 = QgsFeature(4)
        f3.setAttributes(["test_3", 126, 1.7])
        f4 = QgsFeature(5)
        f4.setAttributes(["superpig", 127, 0.8])
        self.assertTrue(layer.dataProvider().addFeatures([f, f1, f2, f3, f4]))

        # no layer
        self.assertFalse(QgsVectorLayerUtils.createFeature(None).isValid())

        # basic tests
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertTrue(f.isValid())
        self.assertEqual(f.fields(), layer.fields())
        self.assertFalse(f.hasGeometry())
        self.assertEqual(f.attributes(), [NULL, NULL, NULL])

        # set geometry
        g = QgsGeometry.fromPointXY(QgsPointXY(100, 200))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertTrue(f.hasGeometry())
        self.assertEqual(f.geometry().asWkt(), g.asWkt())

        # using attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])

        # layer with default value expression
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*4'))
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertEqual(f.attributes(), [NULL, NULL, 12])
        # we do not expect the default value expression to take precedence over the attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])
        # layer with default value expression based on geometry
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*$x'))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        #adjusted so that input value and output feature are the same
        self.assertEqual(f.attributes(), [NULL, NULL, 300.0])
        layer.setDefaultValueDefinition(2, QgsDefaultValue(None))

        # test with violated unique constraints
        layer.setFieldConstraint(1, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and sets to 128
        self.assertEqual(f.attributes(), ['test_1', 128, NULL])
        layer.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)
        # since field 0 and 1 already have values test_1 and 123, the output must be a new unique value
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_4', 128, NULL])

        # test with violated unique constraints and default value expression providing unique value
        layer.setDefaultValueDefinition(1, QgsDefaultValue('130'))
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        self.assertEqual(f.attributes(), ['test_4', 130, NULL])
        # fallback: test with violated unique constraints and default value expression providing already existing value
        # add the feature with the default value:
        self.assertTrue(layer.dataProvider().addFeatures([f]))
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        # and since the default value providing an already existing value (130) it generates a unique value (next int: 131)
        self.assertEqual(f.attributes(), ['test_5', 131, NULL])
        layer.setDefaultValueDefinition(1, QgsDefaultValue(None))

        # test with manually correct unique constraint
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 132})
        self.assertEqual(f.attributes(), ['test_5', 132, NULL])

        """ test creating a feature respecting unique values of postgres provider """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")

        # init connection string
        dbconn = 'dbname=\'qgis_test\''
        if 'QGIS_PGTEST_DB' in os.environ:
            dbconn = os.environ['QGIS_PGTEST_DB']

        # create a vector layer
        pg_layer = QgsVectorLayer('{} table="qgis_test"."authors" sql='.format(dbconn), "authors", "postgres")
        self.assertTrue(pg_layer.isValid())
        # check the default clause
        default_clause = 'nextval(\'qgis_test.authors_pk_seq\'::regclass)'
        self.assertEqual(pg_layer.dataProvider().defaultValueClause(0), default_clause)

        # though default_clause is after the first create not unique (until save), it should fill up all the features with it
        pg_layer.startEditing()
        f = QgsVectorLayerUtils.createFeature(pg_layer)
        self.assertEqual(f.attributes(), [default_clause, NULL])
        self.assertTrue(pg_layer.addFeatures([f]))
#.........这里部分代码省略.........

# 需要导入模块: from qgis.core import QgsFeature [as 别名]
# 或者: from qgis.core.QgsFeature import fields [as 别名]
    def testCreateFeature(self):
        """ test creating a feature respecting defaults and constraints """
        layer = QgsVectorLayer("Point?field=fldtxt:string&field=fldint:integer&field=flddbl:double",
                               "addfeat", "memory")
        # add a bunch of features
        f = QgsFeature()
        f.setAttributes(["test", 123, 1.0])
        f1 = QgsFeature(2)
        f1.setAttributes(["test_1", 124, 1.1])
        f2 = QgsFeature(3)
        f2.setAttributes(["test_2", 125, 2.4])
        f3 = QgsFeature(4)
        f3.setAttributes(["test_3", 126, 1.7])
        f4 = QgsFeature(5)
        f4.setAttributes(["superpig", 127, 0.8])
        self.assertTrue(layer.dataProvider().addFeatures([f, f1, f2, f3, f4]))

        # no layer
        self.assertFalse(QgsVectorLayerUtils.createFeature(None).isValid())

        # basic tests
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertTrue(f.isValid())
        self.assertEqual(f.fields(), layer.fields())
        self.assertFalse(f.hasGeometry())
        self.assertEqual(f.attributes(), [NULL, NULL, NULL])

        # set geometry
        g = QgsGeometry.fromPointXY(QgsPointXY(100, 200))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        self.assertTrue(f.hasGeometry())
        self.assertEqual(f.geometry().asWkt(), g.asWkt())

        # using attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])

        # layer with default value expression
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*4'))
        f = QgsVectorLayerUtils.createFeature(layer)
        self.assertEqual(f.attributes(), [NULL, NULL, 12])
        # we do not expect the default value expression to take precedence over the attribute map
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'a', 2: 6.0})
        self.assertEqual(f.attributes(), ['a', NULL, 6.0])
        # layer with default value expression based on geometry
        layer.setDefaultValueDefinition(2, QgsDefaultValue('3*$x'))
        f = QgsVectorLayerUtils.createFeature(layer, g)
        #adjusted so that input value and output feature are the same
        self.assertEqual(f.attributes(), [NULL, NULL, 300.0])
        layer.setDefaultValueDefinition(2, QgsDefaultValue(None))

        # test with violated unique constraints
        layer.setFieldConstraint(1, QgsFieldConstraints.ConstraintUnique)
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and sets to 128
        self.assertEqual(f.attributes(), ['test_1', 128, NULL])
        layer.setFieldConstraint(0, QgsFieldConstraints.ConstraintUnique)
        # since field 0 and 1 already have values test_1 and 123, the output must be a new unique value
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        self.assertEqual(f.attributes(), ['test_4', 128, NULL])

        # test with violated unique constraints and default value expression providing unique value
        layer.setDefaultValueDefinition(1, QgsDefaultValue('130'))
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        self.assertEqual(f.attributes(), ['test_4', 130, NULL])
        # fallback: test with violated unique constraints and default value expression providing already existing value
        # add the feature with the default value:
        self.assertTrue(layer.dataProvider().addFeatures([f]))
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 123})
        # since field 1 has Unique Constraint, it ignores value 123 that already has been set and adds the default value
        # and since the default value providing an already existing value (130) it generates a unique value (next int: 131)
        self.assertEqual(f.attributes(), ['test_5', 131, NULL])
        layer.setDefaultValueDefinition(1, QgsDefaultValue(None))

        # test with manually correct unique constraint
        f = QgsVectorLayerUtils.createFeature(layer, attributes={0: 'test_1', 1: 132})
        self.assertEqual(f.attributes(), ['test_5', 132, NULL])

# 需要导入模块: from qgis.core import QgsFeature [as 别名]
# 或者: from qgis.core.QgsFeature import fields [as 别名]
        def run_checks():
            self.assertEqual([f.name() for f in vl.fields()], ['fid', 'type', 'value'])

            # expression
            req = QgsFeatureRequest()
            req.setFilterExpression("value=16")
            it = vl.getFeatures(req)
            f = QgsFeature()
            self.assertTrue(it.nextFeature(f))
            self.assertEqual(f.id(), 5)
            self.assertEqual(f.attributes(), [5, 2, 16])
            self.assertEqual([field.name() for field in f.fields()], ['fid', 'type', 'value'])
            self.assertEqual(f.geometry().asWkt(), 'Point (5 5)')

            # filter fid
            req = QgsFeatureRequest()
            req.setFilterFid(5)
            it = vl.getFeatures(req)
            f = QgsFeature()
            self.assertTrue(it.nextFeature(f))
            self.assertEqual(f.id(), 5)
            self.assertEqual(f.attributes(), [5, 2, 16])
            self.assertEqual([field.name() for field in f.fields()], ['fid', 'type', 'value'])
            self.assertEqual(f.geometry().asWkt(), 'Point (5 5)')

            # filter fids
            req = QgsFeatureRequest()
            req.setFilterFids([5])
            it = vl.getFeatures(req)
            f = QgsFeature()
            self.assertTrue(it.nextFeature(f))
            self.assertEqual(f.id(), 5)
            self.assertEqual(f.attributes(), [5, 2, 16])
            self.assertEqual([field.name() for field in f.fields()], ['fid', 'type', 'value'])
            self.assertEqual(f.geometry().asWkt(), 'Point (5 5)')

            # check with subset of attributes
            req = QgsFeatureRequest()
            req.setFilterFids([5])
            req.setSubsetOfAttributes([2])
            it = vl.getFeatures(req)
            f = QgsFeature()
            self.assertTrue(it.nextFeature(f))
            self.assertEqual(f.id(), 5)
            self.assertEqual(f.attributes()[2], 16)
            self.assertEqual([field.name() for field in f.fields()], ['fid', 'type', 'value'])
            self.assertEqual(f.geometry().asWkt(), 'Point (5 5)')

            # filter rect and expression
            req = QgsFeatureRequest()
            req.setFilterExpression("value=16 or value=14")
            req.setFilterRect(QgsRectangle(4.5, 4.5, 5.5, 5.5))
            it = vl.getFeatures(req)
            f = QgsFeature()
            self.assertTrue(it.nextFeature(f))
            self.assertEqual(f.id(), 5)
            self.assertEqual(f.attributes(), [5, 2, 16])
            self.assertEqual([field.name() for field in f.fields()], ['fid', 'type', 'value'])
            self.assertEqual(f.geometry().asWkt(), 'Point (5 5)')

            # filter rect and fids
            req = QgsFeatureRequest()
            req.setFilterFids([3, 5])
            req.setFilterRect(QgsRectangle(4.5, 4.5, 5.5, 5.5))
            it = vl.getFeatures(req)
            f = QgsFeature()
            self.assertTrue(it.nextFeature(f))
            self.assertEqual(f.id(), 5)
            self.assertEqual(f.attributes(), [5, 2, 16])
            self.assertEqual([field.name() for field in f.fields()], ['fid', 'type', 'value'])
            self.assertEqual(f.geometry().asWkt(), 'Point (5 5)')

            # Ensure that orig_ogc_fid is still retrieved even if attribute subset is passed
            req = QgsFeatureRequest()
            req.setSubsetOfAttributes([])
            it = vl.getFeatures(req)
            ids = []
            geoms = {}
            while it.nextFeature(f):
                ids.append(f.id())
                geoms[f.id()] = f.geometry().asWkt()
            self.assertCountEqual(ids, [3, 4, 5])
            self.assertEqual(geoms, {3: 'Point (3 3)', 4: 'Point (4 4)', 5: 'Point (5 5)'})