Removing character from many field names in QGIS

Question

I have a shapefile with ~100 fields. Each field corresponds to a date, the name of each field is something like this 2006-07-05 (year-month-day).

I want to remove the - symbol and have only 20060705. I know I can edit the name in the properties options. I don't want to repeat this ~100 times.

Is there any way to do it programatically?

Answer 1

You should be able to use the "Refactor Fields" tool but it will output a new layer.

You can use PyQGIS and .renameAttribute() method. The code below is going to replace all - with nothing/an empty string in all columns with a - in the name.

⚠️ Backup your layer first, the code will change the layer in place.

layer = QgsProject.instance().mapLayersByName("datenames")[0] #Create a layer object, ...
# ... replace datenames with the name of your layer.

for field in layer.fields(): #For each field in your layer
    if "-" in field.name(): #If there is a - in the field name
        new_name = field.name().replace("-", "") #Create a new name by replacing
        #  - with nothing
        with edit(layer): #Start an edit session
            idx = layer.fields().indexFromName(field.name()) #Find the fields index
            layer.renameAttribute(idx, new_name) #Rename the field by using the index and the new name

Answer 2

A one-time operation

There is a QGIS Plugin available for this purpose "Rename Field" with a simple interface. Can be found under Plugins > Rename Field > Rename field.

A multiple-time operation

It is also a PyQGIS approach, a bit similar to what @Bera suggested.

It utilizes the renameAttributes() method inherited from the QgsVectorDataProvider class.

⚠️ Do not forget to backup your layer first, the code will change the layer in place.

# imports
from qgis.core import QgsProject

# getting a layer by its name
layer = QgsProject.instance().mapLayersByName("YOUR_LAYER_NAME")[0]
# accessing data provider of the layer
dp = layer.dataProvider()

# a dict to store field indexes and their new names
new_fields = {}

# looping over each field in the layer
for field in layer.fields():
    name = field.name() # getting field original name
    if "_" in name: # matching condition
        ind = dp.fieldNameIndex(name) # finding field index
        new_fields[ind] = name.replace("_", "")

# changing field names
dp.renameAttributes(new_fields)
# updating the original layer
layer.updateFields()

Note: The order of fields visualized in the attribute table might be changed.

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References:

• Renaming attributes/fields in shapefile attribute table using QGIS
• Renaming attribute via pyQGis and data provider