Here’s the relevant example from the documentation on RethinkDB’s website: http://rethinkdb.com/docs/cookbook/python/#removing-a-field-from-a-document
To remove a field from all documents in a table, you need to use replace to update the document to not include the desired field (using without):
r.db('db').table('user').replace(r.row.without('key'))
To remove the field from one specific document in the table:
r.db('db').table('user').get('id').replace(r.row.without('key'))
You can change the selection of documents to update by using any of the selectors in the API (http://rethinkdb.com/api/), e.g. db, table, get, get_all, between, filter.