Sequence IDS

transformers/tokenization_bert.py

@@ -204,6 +204,24 @@ class BertTokenizer(PreTrainedTokenizer):
 
         return cls + token_ids_0 + sep + token_ids_1 + sep
 
+    def get_sequence_ids(self, token_ids_0, token_ids_1=None):
+        """
+        Retrieves sequence ids from a token list that has no special tokens added. This method is called when adding
+        special tokens using the tokenizer ``prepare_for_model`` or ``encode_plus`` methods.
+
+        Args:
+            token_ids_0: list of ids (must not contain special tokens)
+            token_ids_1: Optional list of ids (must not contain special tokens), necessary when fetching sequence ids
+            for sequence pairs
+
+        Returns:
+            A list of integers in the range [0, 1]: 0 for a special token, 1 for a sequence token.
+        """
+        if token_ids_1:
+            return [0] + ([1] * len(token_ids_0)) + [0] + ([1] * len(token_ids_1)) + [0]
+        else:
+            return [0] + ([1] * len(token_ids_0)) + [0]
+
     def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1):
         """
         Creates a mask from the two sequences passed to be used in a sequence-pair classification task.