OWPreprocess Text: Add Lemmagen normalizer

doc/widgets/preprocesstext.md

@@ -39,6 +39,7 @@ Preprocesses corpus with selected methods.
     - [Snowball Stemmer](http://snowballstem.org/) applies an improved version of Porter stemmer (Porter2). Set the language for normalization, default is English.
     - [WordNet Lemmatizer](http://wordnet.princeton.edu/) applies a networks of cognitive synonyms to tokens based on a large lexical database of English.
     - [UDPipe](http://ufal.mff.cuni.cz/udpipe/1) applies a [pre-trained model](https://lindat.mff.cuni.cz/repository/xmlui/handle/11234/1-2998?show=full) for normalizing data.
+    - [Lemmagen](https://github.com/vpodpecan/lemmagen3) applies a pre-trained model for normalizing data.
 5. **Filtering** removes or keeps a selection of words.
     - *Stopwords* removes stopwords from text (e.g. removes 'and', 'or', 'in'...). Select the language to filter by, English is set as default. You can also load your own list of stopwords provided in a simple \*.txt file with one stopword per line.
       ![](images/stopwords.png)

orangecontrib/text/preprocess/normalize.py

@@ -2,6 +2,7 @@
 import os
 import json
 import ufal.udpipe as udpipe
+from lemmagen3 import Lemmatizer
 import serverfiles
 from nltk import stem
 from requests.exceptions import ConnectionError
@@ -14,7 +15,7 @@
 from orangecontrib.text.preprocess import Preprocessor, TokenizedPreprocessor
 
 __all__ = ['BaseNormalizer', 'WordNetLemmatizer', 'PorterStemmer',
-           'SnowballStemmer', 'UDPipeLemmatizer']
+           'SnowballStemmer', 'UDPipeLemmatizer', 'LemmagenLemmatizer']
 
 
 class BaseNormalizer(TokenizedPreprocessor):
@@ -52,7 +53,8 @@ class PorterStemmer(BaseNormalizer):
 
 class SnowballStemmer(BaseNormalizer):
     name = 'Snowball Stemmer'
-    supported_languages = [l.capitalize() for l in stem.SnowballStemmer.languages]
+    supported_languages = [l.capitalize() for l in
+                           stem.SnowballStemmer.languages]
 
     def __init__(self, language='English'):
         self.normalizer = stem.SnowballStemmer(language.lower())
@@ -70,7 +72,7 @@ def file_to_name(file):
 
 
 def file_to_language(file):
-    return file[:file.find('ud')-1]\
+    return file[:file.find('ud') - 1] \
         .replace('-', ' ').replace('_', ' ').capitalize()
 
 
@@ -184,3 +186,37 @@ def __getstate__(self):
         state['_UDPipeLemmatizer__model'] = None
         state['_UDPipeLemmatizer__output_format'] = None
         return state
+
+
+class LemmagenLemmatizer(BaseNormalizer):
+    name = 'Lemmagen Lemmatizer'
+    lemmagen_languages = {
+        "Bulgarian": "bg",
+        "Croatian": "hr",
+        "Czech": "cs",
+        "English": "en",
+        "Estonian": "et",
+        "Farsi/Persian": "fa",
+        "French": "fr",
+        "German": "de",
+        "Hungarian": "hu",
+        "Italian": "it",
+        "Macedonian": "mk",
+        "Polish": "pl",
+        "Romanian": "ro",
+        "Russian": "ru",
+        "Serbian": "sr",
+        "Slovak": "sk",
+        "Slovenian": "sl",
+        "Spanish": "es",
+        "Ukrainian": "uk"
+    }
+
+    def __init__(self, language='English'):
+        self.lemmatizer = Lemmatizer(self.lemmagen_languages[language])
+
+    def normalizer(self, token):
+        t = self.lemmatizer.lemmatize(token)
+        # sometimes Lemmagen returns an empty string, return original tokens
+        # in this case
+        return t if t else token

orangecontrib/text/tests/test_preprocess.py

@@ -8,6 +8,7 @@
 
 import nltk
 from gensim import corpora
+from lemmagen3 import Lemmatizer
 from requests.exceptions import ConnectionError
 import numpy as np
 
@@ -78,7 +79,8 @@ def _preprocess(cls, string):
                 return string.split()
 
         p = SpaceTokenizer()
-        array = np.array([sent.split() for sent in self.corpus.documents])
+        array = np.array([sent.split() for sent in self.corpus.documents],
+                         dtype=object)
         np.testing.assert_equal(p(self.corpus).tokens, array)
 
     def test_token_normalizer(self):
@@ -101,7 +103,7 @@ def _check(self, token):
 
         p = LengthFilter()
         tokens = np.array([[token for token in doc.split() if len(token) < 4]
-                           for doc in self.corpus.documents])
+                           for doc in self.corpus.documents], dtype=object)
         np.testing.assert_equal(p(self.corpus).tokens, tokens)
 
     def test_inplace(self):
@@ -238,6 +240,13 @@ def test_call_UDPipe(self):
         self.assertTrue(corpus.has_tokens())
         self.assertEqual(len(corpus.used_preprocessor.preprocessors), 2)
 
+    def test_call_lemmagen(self):
+        pp = preprocess.LemmagenLemmatizer()
+        self.assertFalse(self.corpus.has_tokens())
+        corpus = pp(self.corpus)
+        self.assertTrue(corpus.has_tokens())
+        self.assertEqual(len(corpus.used_preprocessor.preprocessors), 2)
+
     def test_function(self):
         stemmer = preprocess.BaseNormalizer()
         stemmer.normalizer = lambda x: x[:-1]
@@ -291,6 +300,14 @@ def test_udpipe_deepcopy(self):
         self.assertEqual(list(copied(self.corpus).tokens[0]),
                          ['gora', 'na', 'gora', 'hiša', 'goreti'])
 
+    def test_lemmagen(self):
+        normalizer = preprocess.LemmagenLemmatizer('Slovenian')
+        token = 'veselja'
+        self.assertEqual(
+            normalizer._preprocess(token),
+            Lemmatizer("sl").lemmatize(token)
+        )
+
 
 class UDPipeModelsTests(unittest.TestCase):
     def test_label_transform(self):

orangecontrib/text/widgets/owpreprocess.py

@@ -384,11 +384,12 @@ def __repr__(self):
 
 
 class NormalizationModule(SingleMethodModule):
-    Porter, Snowball, WordNet, UDPipe = range(4)
+    Porter, Snowball, WordNet, UDPipe, Lemmagen = range(5)
     Methods = {Porter: PorterStemmer,
                Snowball: SnowballStemmer,
                WordNet: WordNetLemmatizer,
-               UDPipe: UDPipeLemmatizer}
+               UDPipe: UDPipeLemmatizer,
+               Lemmagen: LemmagenLemmatizer}
     DEFAULT_METHOD = Porter
     DEFAULT_LANGUAGE = "English"
     DEFAULT_USE_TOKE = False
@@ -397,6 +398,7 @@ def __init__(self, parent=None, **kwargs):
         super().__init__(parent, **kwargs)
         self.__snowball_lang = self.DEFAULT_LANGUAGE
         self.__udpipe_lang = self.DEFAULT_LANGUAGE
+        self.__lemmagen_lang = self.DEFAULT_LANGUAGE
         self.__use_tokenizer = self.DEFAULT_USE_TOKE
 
         self.__combo_sbl = ComboBox(
@@ -410,6 +412,10 @@ def __init__(self, parent=None, **kwargs):
         self.__check_use = QCheckBox("UDPipe tokenizer",
                                      checked=self.DEFAULT_USE_TOKE)
         self.__check_use.clicked.connect(self.__set_use_tokenizer)
+        self.__combo_lemm = ComboBox(
+            self, LemmagenLemmatizer.lemmagen_languages,
+            self.__lemmagen_lang, self.__set_lemmagen_lang
+        )
 
         label = QLabel("Language:")
         label.setAlignment(Qt.AlignRight | Qt.AlignVCenter)
@@ -425,6 +431,11 @@ def __init__(self, parent=None, **kwargs):
         self.layout().setColumnStretch(2, 1)
         self.__enable_udpipe()
 
+        label = QLabel("Language:")
+        label.setAlignment(Qt.AlignRight | Qt.AlignVCenter)
+        self.layout().addWidget(label, self.Lemmagen, 1)
+        self.layout().addWidget(self.__combo_lemm, self.Lemmagen, 2)
+
     def __enable_udpipe(self):
         enable = bool(self.__combo_udl.items)
         layout = self.layout()  # type: QGridLayout
@@ -441,6 +452,8 @@ def setParameters(self, params: Dict):
         self.__set_udpipe_lang(udpipe_lang)
         use_tokenizer = params.get("udpipe_tokenizer", self.DEFAULT_USE_TOKE)
         self.__set_use_tokenizer(use_tokenizer)
+        lemmagen_lang = params.get("lemmagen_language", self.DEFAULT_LANGUAGE)
+        self.__set_lemmagen_lang(lemmagen_lang)
 
     def _set_method(self, method: int):
         super()._set_method(method)
@@ -462,6 +475,14 @@ def __set_udpipe_lang(self, language: str):
             if self.method == self.UDPipe:
                 self.edited.emit()
 
+    def __set_lemmagen_lang(self, language: str):
+        if self.__lemmagen_lang != language:
+            self.__lemmagen_lang = language
+            self.__combo_lemm.setCurrentText(language)
+            self.changed.emit()
+            if self.method == self.Lemmagen:
+                self.edited.emit()
+
     def __set_use_tokenizer(self, use: bool):
         if self.__use_tokenizer != use:
             self.__use_tokenizer = use
@@ -474,7 +495,8 @@ def parameters(self) -> Dict:
         params = super().parameters()
         params.update({"snowball_language": self.__snowball_lang,
                        "udpipe_language": self.__udpipe_lang,
-                       "udpipe_tokenizer": self.__use_tokenizer})
+                       "udpipe_tokenizer": self.__use_tokenizer,
+                       "lemmagen_language": self.__lemmagen_lang})
         return params
 
     @staticmethod
@@ -488,6 +510,8 @@ def createinstance(params: Dict) -> BaseNormalizer:
             def_use = NormalizationModule.DEFAULT_USE_TOKE
             args = {"language": params.get("udpipe_language", def_lang),
                     "use_tokenizer": params.get("udpipe_tokenizer", def_use)}
+        elif method == NormalizationModule.Lemmagen:
+            args = {"language": params.get("lemmagen_language", def_lang)}
         return NormalizationModule.Methods[method](**args)
 
     def __repr__(self):
@@ -497,6 +521,8 @@ def __repr__(self):
         elif self.method == self.UDPipe:
             text = f"{text} ({self.__udpipe_lang}, " \
                    f"Tokenize: {['No', 'Yes'][self.__use_tokenizer]})"
+        elif self.method == self.Lemmagen:
+            text = f"{text} ({self.__lemmagen_lang})"
         return text
 
 

orangecontrib/text/widgets/tests/test_owpreprocess.py

@@ -358,6 +358,10 @@ def combo_sbl(self):
     def combo_udl(self):
         return self.editor._NormalizationModule__combo_udl
 
+    @property
+    def combo_lemm(self):
+        return self.editor._NormalizationModule__combo_lemm
+
     @property
     def check_use(self):
         return self.editor._NormalizationModule__check_use
@@ -374,18 +378,21 @@ def test_parameters(self):
         params = {"method": NormalizationModule.Porter,
                   "snowball_language": "English",
                   "udpipe_language": "English",
+                  "lemmagen_language": "English",
                   "udpipe_tokenizer": False}
         self.assertDictEqual(self.editor.parameters(), params)
 
     def test_set_parameters(self):
         params = {"method": NormalizationModule.UDPipe,
                   "snowball_language": "Dutch",
                   "udpipe_language": "Finnish",
+                  "lemmagen_language": "Bulgarian",
                   "udpipe_tokenizer": True}
         self.editor.setParameters(params)
         self.assertDictEqual(self.editor.parameters(), params)
         self.assertEqual(self.combo_sbl.currentText(), "Dutch")
         self.assertEqual(self.combo_udl.currentText(), "Finnish")
+        self.assertEqual(self.combo_lemm.currentText(), "Bulgarian")
         self.assertTrue(self.check_use.isChecked())
 
     def test_createinstance(self):

requirements.txt

@@ -19,3 +19,4 @@ ufal.udpipe >=1.2.0.3
 orange-widget-base >=4.12.0
 yake
 conllu
+lemmagen3