Batch remove attributes

Question

I'm having a little trouble using the merge command in QGIS. All the files have a range of different attributes, with some attribute headers in common. Some of these have different data format types for the common column, so when I try to merge them I get an error message.

I'm happy to delete all columns other one I've batch inserted, but how can I batch delete all columns other than one? I know I can use the Drop Fields Tool (/Delete Columns) but I'd have to individually select each column I want to delete in each of the layers.

Answer 1

If the field that you want to remain on every file has the same name, this will help:

import glob
from qgis.core import *

filter_ = "c:/_path_/*.shp" # or any file type supported by QgsVectorLayer    
field_name_to_remain = "field_name"

for file in glob.glob(filter_):
    layer = QgsVectorLayer(file, 'temp', 'ogr') # load file
    dpr = layer.dataProvider() # get dataprovider
    fields = dpr.fields() # get fields - QgsFields object

    field_index_list = []
    for f in fields:
        if f.name() != field_name_to_remain : 
            i = dpr.fieldNameIndex(f.name()) # get field index number
            field_index_list.append(i) # add to delete list

    dpr.deleteAttributes(field_index_list) # delete other fields
    layer.updateFields()

    del layer # from memory

NOTE: Before running the code, back up all files in your folder. Because the code change all original files in that folder.

Answer 2

The refactor tool should work for you