code: def export_select_fields_csv_action(
          description="Export selected objects as CSV file",
          fields=None, exclude=None, header=True):
      
      def export_as_csv(modeladmin, request, queryset):
          """
          Generic csv export admin action.
          based on http://djangosnippets.org/snippets/1697/
          """
          opts = modeladmin.model._meta
          field_names = [field.name for field in opts.fields]
          labels = []
          if exclude:
              field_names = [v for v in field_names if v not in exclude]
          elif fields:
              field_names = [k for k, v in fields if k in field_names]
              labels = [v for k, v in fields if k in field_names]
  
          response = HttpResponse(mimetype='text/csv')
          response['Content-Disposition'] = ('attachment; filename=%s.csv'
                                             % unicode(opts).replace('.', '_'))
  
          writer = csv.writer(response)
          if header:
              if labels:
                  writer.writerow(labels)
              else:
                  writer.writerow(field_names)
          for obj in queryset:
              writer.writerow([unicode(getattr(obj, field)).encode('utf-8')
                              for field in field_names])
          return response
      export_as_csv.short_description = description
      return export_as_csv
docs: This function returns an export csv action
  
      'fields' is a list of tuples denoting the field and label to be exported.
      Labels make up the header row of the exported file if header=True.
  
          fields=[
                  ('field1', 'label1'),
                  ('field2', 'label2'),
                  ('field3', 'label3'),
              ]
  
      'exclude' is a flat list of fields to exclude. If 'exclude' is passed,
      'fields' will not be used. Either use 'fields' or 'exclude.'
  
          exclude=['field1', 'field2', field3]
  
      'header' is whether or not to output the column names as the first row
  
      From: http://djangosnippets.org/snippets/2712/
      Which is in turn based on: http://djangosnippets.org/snippets/2020/