!2375 Add Python Tokenizer

Merge pull request !2375 from h.farahat/python_tokenizer

mindspore/dataset/text/__init__.py

@@ -22,12 +22,13 @@ from .utils import to_str, to_bytes, JiebaMode, Vocab, NormalizeForm
 
 __all__ = [
     "Lookup", "JiebaTokenizer", "UnicodeCharTokenizer", "Ngram",
-    "to_str", "to_bytes", "JiebaMode", "Vocab", "WordpieceTokenizer", "TruncateSequencePair", "ToNumber"
+    "to_str", "to_bytes", "JiebaMode", "Vocab", "WordpieceTokenizer", "TruncateSequencePair", "ToNumber",
+    "PythonTokenizer"
 ]
 
 if platform.system().lower() != 'windows':
     from .transforms import UnicodeScriptTokenizer, WhitespaceTokenizer, CaseFold, NormalizeUTF8, \
-        RegexReplace, RegexTokenizer, BasicTokenizer, BertTokenizer
+        RegexReplace, RegexTokenizer, BasicTokenizer, BertTokenizer, PythonTokenizer
 
     __all__.append(["UnicodeScriptTokenizer", "WhitespaceTokenizer", "CaseFold", "NormalizeUTF8",
                     "RegexReplace", "RegexTokenizer", "BasicTokenizer", "BertTokenizer", "NormalizeForm"])

mindspore/dataset/text/transforms.py

@@ -18,13 +18,14 @@ c transforms for all text related operators
 import os
 import re
 import platform
+import numpy as np
 
 import mindspore._c_dataengine as cde
 
-from .utils import JiebaMode, NormalizeForm
+from .utils import JiebaMode, NormalizeForm, to_str
 from .validators import check_lookup, check_jieba_add_dict, \
     check_jieba_add_word, check_jieba_init, check_ngram, check_pair_truncate, \
-    check_to_number
+    check_to_number, check_python_tokenizer
 from ..core.datatypes import mstype_to_detype
 
 
@@ -418,3 +419,25 @@ class ToNumber(cde.ToNumberOp):
         data_type = mstype_to_detype(data_type)
         self.data_type = str(data_type)
         super().__init__(data_type)
+
+
+class PythonTokenizer:
+    """
+    Callable class to be used for user-defined string tokenizer.
+    Args:
+        tokenizer (Callable): Python function that takes a `str` and returns a list of `str` as tokens.
+
+    Examples:
+        >>> def my_tokenizer(line):
+        >>>     return line.split()
+        >>> data = data.map(operations=PythonTokenizer(my_tokenizer))
+    """
+
+    @check_python_tokenizer
+    def __init__(self, tokenizer):
+        self.tokenizer = np.vectorize(lambda x: np.array(tokenizer(x), dtype='U'), signature='()->(n)')
+
+    def __call__(self, in_array):
+        in_array = to_str(in_array)
+        tokens = self.tokenizer(in_array)
+        return tokens

mindspore/dataset/text/validators.py

@@ -411,3 +411,25 @@ def check_to_number(method):
         return method(self, **kwargs)
 
     return new_method
+
+
+def check_python_tokenizer(method):
+    """A wrapper that wraps a parameter check to the original function (PythonTokenizer)."""
+
+    @wraps(method)
+    def new_method(self, *args, **kwargs):
+        tokenizer = (list(args) + [None])[0]
+        if "tokenizer" in kwargs:
+            tokenizer = kwargs.get("tokenizer")
+
+        if tokenizer is None:
+            raise ValueError("tokenizer is a mandatory parameter.")
+
+        if not callable(tokenizer):
+            raise TypeError("tokenizer is not a callable python function")
+
+        kwargs["tokenizer"] = tokenizer
+
+        return method(self, **kwargs)
+
+    return new_method

tests/ut/python/dataset/test_python_tokenizer.py

@@ -0,0 +1,52 @@
+# Copyright 2020 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""
+Testing PythonTokenizer op in DE
+"""
+import mindspore.dataset as ds
+import mindspore.dataset.text as text
+from mindspore import log as logger
+
+DATA_FILE = "../data/dataset/testTokenizerData/1.txt"
+
+
+def test_whitespace_tokenizer_ch():
+    """
+    Test PythonTokenizer
+    """
+    whitespace_strs = [["Welcome", "to", "Beijing!"],
+                       ["北京欢迎您！"],
+                       ["我喜欢English!"],
+                       [""]]
+
+    def my_tokenizer(line):
+        words = line.split()
+        if not words:
+            return [""]
+        return words
+
+    dataset = ds.TextFileDataset(DATA_FILE, shuffle=False)
+    tokenizer = text.PythonTokenizer(my_tokenizer)
+    dataset = dataset.map(operations=tokenizer, num_parallel_workers=1)
+    tokens = []
+    for i in dataset.create_dict_iterator():
+        s = text.to_str(i['text']).tolist()
+        tokens.append(s)
+    logger.info("The out tokens is : {}".format(tokens))
+    assert whitespace_strs == tokens
+
+
+if __name__ == '__main__':
+    test_whitespace_tokenizer_ch()