ClassifierBasedPOSTagger class :
- This is a subclass of ClassifierBasedTagger that uses a classification technique to perform part-of-speech tagging.
- From words, functions are extracted and then passed to the internal classifier.
- It classifies the functions and returns a label, that is, a part of speech tag.
- The feature detector finds suffixes of several lengths, matches regular expressions and looks at the history of unigrams, bigrams, etc. trigrams to get a fairly complete set of functions for each word.
Code # 1: Using ClassifierBasedPOSTagger
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Output:
Accuracy: 0.9309734513274336
The ClassifierBasedPOSTagger class inherits from ClassifierBasedTagger and only implements the feature_detector () method. All training and tagging is done in the ClassifierBasedTagger.
Code # 2: Using the MaxentClassifier
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Output:
Accuracy: 0.9258363911072739
custom feature detector detection features
There are two ways to do this:
- Subclass ClassifierBasedTagger and implement the feature_detector () method.
- Pass the feature as an argument of the feature_detector keyword in the ClassifierBasedTagger on initialization.
Code # 3: Custom Feature Detector
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Output:
Accuracy: 0.8733865745737104