Search and Replace text in All Fields in QGIS 3

Question

I want to replace a string in ALL FIELDS / Columns of table without having to do it using field calculator in every field manually using replace( "RoadName1" ,'Wharf','WharfXXX').

I have

layer = iface.activeLayer()
searchText = "Wharf"
replaceText = "WharfXXX"
for field in layer.fields():
    fieldName=field.name()
    print (fieldName)
    for feature in layer.getFeatures():
        inText=str(feature[fieldName])
        #print (inText)
        if searchText in inText:
        #try QgsStringReplacement
            QgsStringReplacement(inText,replaceText, False, False)
        #try Field Calculator

            print ("Replaced %s with %s" %(inText,replaceText))
        else:
            #print ("not found")
            pass

It seems to work but I am not seeing any changes in the dataset.

I can't find any example implementations of https://qgis.org/api/classQgsStringReplacement.html

Does this function do what I think it's supposed to -i.e. replace text when it matches?

I guess I could configure field calc to use these inputs but the function above seems cleaner in the long run.

processing.run("qgis:fieldcalculator", {'INPUT':'test.tab|layername=test','FIELD_NAME':'RoadName','FIELD_TYPE':0,'FIELD_LENGTH':10,'FIELD_PRECISION':3,'NEW_FIELD':False,'FORMULA':' replace( \"RoadName\" ,\'Warner\',\'WarnerXXX\')','OUTPUT':'memory:'})

Answer 1

You can try code below (backup data prior):

layer = iface.activeLayer()
textfields = [f.name() for f in layer.fields() if f.typeName()=='String']

replacedict = {'Hus,':'HusXYZ,','1':'ONE'}

with edit(layer):
    for feature in layer.getFeatures():
        for f in textfields:
            value = feature[f]
            if type(value)== str:
                new_value = ' '.join([replacedict[word] if word in replacedict else word for word in value.split()])
                _=feature.setAttribute(feature.fieldNameIndex(f), new_value)
                _=layer.updateFeature(feature)

From:

To:

If you want to replace parts of Words you can do:

layer = iface.activeLayer()
textfields = [f.name() for f in layer.fields() if f.typeName()=='String']

with edit(layer):
    for feature in layer.getFeatures():
        for f in textfields:
            value = feature[f]
            if type(value)== str:
                new_value = value.replace('Wharf','WharfXXX')
                _=feature.setAttribute(feature.fieldNameIndex(f), new_value)
                _=layer.updateFeature(feature)

Answer 2

You can solve your problem using layer.changeAttributeValue() in an edit session.

layer = iface.activeLayer()
searchText = "Wharf"
replaceText = "WharfXXX"

# Start edit session for the layer
layer.startEditing()

for field in layer.fields():
    fieldName = field.name()
    # get field index
    fieldIndex = layer.fields().indexFromName(fieldName)

    for feature in layer.getFeatures():
        inText = str(feature[fieldName])

        if searchText in inText:
            # change inText
            outText = inText.replace(searchText, replaceText)
            # change field value of the attribute (in memory)
            layer.changeAttributeValue(feature.id(), fieldIndex, outText)

# save changes
layer.commitChanges()

---

Or you can use layer.dataProvider().changeAttributeValues(). In that case, you can change multiple fields at once. To see changes you may need to reopen the attribute table.

layer = iface.activeLayer()
searchText = "Wharf"
replaceText = "WharfXXX"

# get data provider
dpr = layer.dataProvider()

for field in layer.fields():
    fieldName=field.name()

    for feature in layer.getFeatures():
        inText = str(feature[fieldName])
        # get field index
        fieldIndex = layer.fields().indexFromName(fieldName)

        if searchText in inText:
            # change inText
            outText = inText.replace(searchText, replaceText)
            # save changes
            dpr.changeAttributeValues({feature.id(): {fieldIndex: outText}})