Add standardized get_vocab method to tokenizers

src/transformers/tokenization_albert.py

@@ -114,6 +114,11 @@ class AlbertTokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.sp_model)
 
+    def get_vocab(self):
+        vocab = {self.convert_ids_to_tokens(i): i for i in range(self.vocab_size)}
+        vocab.update(self.added_tokens_encoder)
+        return vocab
+
     def __getstate__(self):
         state = self.__dict__.copy()
         state["sp_model"] = None

src/transformers/tokenization_bert.py

@@ -195,6 +195,9 @@ class BertTokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.vocab)
 
+    def get_vocab(self):
+        return dict(self.vocab, **self.added_tokens_encoder)
+
     def _tokenize(self, text):
         split_tokens = []
         if self.do_basic_tokenize:

src/transformers/tokenization_ctrl.py

@@ -147,6 +147,9 @@ class CTRLTokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.encoder)
 
+    def get_vocab(self):
+        return dict(self.encoder, **self.added_tokens_encoder)
+
     def bpe(self, token):
         if token in self.cache:
             return self.cache[token]

src/transformers/tokenization_gpt2.py

@@ -149,6 +149,9 @@ class GPT2Tokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.encoder)
 
+    def get_vocab(self):
+        return dict(self.encoder, **self.added_tokens_encoder)
+
     def bpe(self, token):
         if token in self.cache:
             return self.cache[token]

src/transformers/tokenization_openai.py

@@ -125,6 +125,9 @@ class OpenAIGPTTokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.encoder)
 
+    def get_vocab(self):
+        return dict(self.encoder, **self.added_tokens_encoder)
+
     def bpe(self, token):
         word = tuple(token[:-1]) + (token[-1] + "</w>",)
         if token in self.cache:

src/transformers/tokenization_t5.py

@@ -119,6 +119,11 @@ class T5Tokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return self.sp_model.get_piece_size() + self._extra_ids
 
+    def get_vocab(self):
+        vocab = {self.convert_ids_to_tokens(i): i for i in range(self.vocab_size)}
+        vocab.update(self.added_tokens_encoder)
+        return vocab
+
     def __getstate__(self):
         state = self.__dict__.copy()
         state["sp_model"] = None

src/transformers/tokenization_transfo_xl.py

@@ -273,6 +273,9 @@ class TransfoXLTokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.idx2sym)
 
+    def get_vocab(self):
+        return dict(self.sym2idx, **self.added_tokens_encoder)
+
     def _tokenize(self, line, add_eos=False, add_double_eos=False):
         line = line.strip()
         # convert to lower case

src/transformers/tokenization_utils.py

@@ -286,6 +286,10 @@ class PreTrainedTokenizer(object):
         """ Ids of all the additional special tokens in the vocabulary (list of integers). Log an error if used while not having been set. """
         return self.convert_tokens_to_ids(self.additional_special_tokens)
 
+    def get_vocab(self):
+        """ Returns the vocabulary as a dict of {token: index} pairs. `tokenizer.get_vocab()[token]` is equivalent to `tokenizer.convert_tokens_to_ids(token)` when `token` is in the vocab. """
+        raise NotImplementedError()
+
     def __init__(self, max_len=None, **kwargs):
         self._bos_token = None
         self._eos_token = None

src/transformers/tokenization_xlm.py

@@ -662,6 +662,9 @@ class XLMTokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.encoder)
 
+    def get_vocab(self):
+        return dict(self.encoder, **self.added_tokens_encoder)
+
     def bpe(self, token):
         word = tuple(token[:-1]) + (token[-1] + "</w>",)
         if token in self.cache:

src/transformers/tokenization_xlm_roberta.py

@@ -190,6 +190,11 @@ class XLMRobertaTokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.sp_model) + len(self.fairseq_tokens_to_ids)
 
+    def get_vocab(self):
+        vocab = {self.convert_ids_to_tokens(i): i for i in range(self.vocab_size)}
+        vocab.update(self.added_tokens_encoder)
+        return vocab
+
     def _tokenize(self, text):
         return self.sp_model.EncodeAsPieces(text)
 

src/transformers/tokenization_xlnet.py

@@ -114,6 +114,11 @@ class XLNetTokenizer(PreTrainedTokenizer):
     def vocab_size(self):
         return len(self.sp_model)
 
+    def get_vocab(self):
+        vocab = {self.convert_ids_to_tokens(i): i for i in range(self.vocab_size)}
+        vocab.update(self.added_tokens_encoder)
+        return vocab
+
     def __getstate__(self):
         state = self.__dict__.copy()
         state["sp_model"] = None

tests/test_tokenization_common.py

@@ -542,3 +542,23 @@ class TokenizerTesterMixin:
         print(new_tokenizer.init_kwargs)
         assert tokenizer.init_kwargs["random_argument"] is True
         assert new_tokenizer.init_kwargs["random_argument"] is False
+
+    def test_get_vocab(self):
+        tokenizer = self.get_tokenizer()
+        vocab = tokenizer.get_vocab()
+
+        self.assertIsInstance(vocab, dict)
+        self.assertEqual(len(vocab), len(tokenizer))
+
+        for word, ind in vocab.items():
+            self.assertEqual(tokenizer.convert_tokens_to_ids(word), ind)
+            self.assertEqual(tokenizer.convert_ids_to_tokens(ind), word)
+
+        tokenizer.add_tokens(["asdfasdfasdfasdf"])
+        vocab = tokenizer.get_vocab()
+        self.assertIsInstance(vocab, dict)
+        self.assertEqual(len(vocab), len(tokenizer))
+
+        for word, ind in vocab.items():
+            self.assertEqual(tokenizer.convert_tokens_to_ids(word), ind)
+            self.assertEqual(tokenizer.convert_ids_to_tokens(ind), word)