2

I have a gpkg with a column called name. I am trying to use PyQGIS to find any of the values in this column that starts with r and then contain e or x. I would then like to update a new column I've created called Relevant_Pipework with either Relevant or Not Relevant based on whether the regex has matched. Below is the code I've written.

import re
from qgis.core import (
    QgsVectorLayer
)

path_to_gpkg = "D:/Pipework.gpkg"

Water_Pipes_Layer = path_to_gpkg + "|Water_Pipes"

vlayer = QgsVectorLayer(Water_Pipes_Layer, "Water_Pipes", "ogr")
if not vlayer.isValid():
    print("Layer failed to load!")
else:
    QgsProject.instance().addMapLayer(vlayer)

layer = iface.activeLayer()
prov = layer.dataProvider()
pattern = '[rex]'

features = layer.getFeatures()

layer.startEditing()

if layer.dataProvider().fieldNameIndex("Relevant_Pipework") == -1:
    layer.dataProvider().addAttributes([QgsField("Relevant_Pipework", QVariant.String)])
    layer.updateFields()


for feat in features:
    Regex_Search_Field = feature['name']
    Regex_String = re.compile(pattern)
    Regex_Match = Regex_String.search(Regex_Search_Field)
    if Regex_Match:
        layer.changeAttributeValue(feat.id(), 11, "Match")
    else:
        layer.changeAttributeValue(feat.id(), 11, "No Match")

1 Answer 1

2

I think your regex needs to be ^r.*[ex].*$ - In general it's always worth using a regex tester like https://regex101.com/ to try these out.

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