Text porterstemmermode

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PorterStemmerMode

Which of the Porter algorithm's two published forms PorterStemmer.Stem applies.

public enum PorterStemmerMode { OriginalAlgorithm, MartinExtensions }

Members — OriginalAlgorithm is the 1980 paper's rules as printed: abli becomes able, logi is kept, and a word of one or two letters is stemmed like any other. It is nltk's ORIGINAL_ALGORITHM, and the default. MartinExtensions is the three departures Martin Porter's own reference implementation makes from the paper: bli becomes ble, logi becomes log, and a word of one or two letters comes back lowercased and unstemmed. It is nltk's MARTIN_EXTENSIONS.

Example — the two modes on the words they part over.

using Lodestar.Text.Stemming;

string paper = PorterStemmer.Stem("accessibly", PorterStemmerMode.OriginalAlgorithm);  // => accessibli
string martin = PorterStemmer.Stem("accessibly", PorterStemmerMode.MartinExtensions);  // => access

Remarks — pick the mode the index you are matching was built with; neither is better English. An index built by Martin's C or Java implementation, or by a port of it, reads MartinExtensions. nltk's own default, NLTK_EXTENSIONS, is a third form with rules of its own and is not offered: EnglishSnowballStemmer is the stemmer to reach for when no existing index fixes the choice.

Applies to — net10.0, netstandard2.0.

See also — PorterStemmer.Stem, PorterStemmer.