quanteda (version 0.99)

tokens_wordstem: stem the terms in an object

Description

Apply a stemmer to words. This is a wrapper to wordStem designed to allow this function to be called without loading the entire SnowballC package. wordStem uses Martin Porter's stemming algorithm and the C libstemmer library generated by Snowball.

Usage

tokens_wordstem(x, language = quanteda_options("language_stemmer"))
char_wordstem(x, language = quanteda_options("language_stemmer"))
dfm_wordstem(x, language = quanteda_options("language_stemmer"))

Arguments

x

a character, tokens, or dfm object whose word stems are to be removed. If tokenized texts, the tokenization must be word-based.

language

the name of a recognized language, as returned by getStemLanguages, or a two- or three-letter ISO-639 code corresponding to one of these languages (see references for the list of codes)

Value

tokens_wordstem returns a tokens object whose word types have been stemmed.

char_wordstem returns a character object whose word types have been stemmed.

dfm_wordstem returns a dfm object whose word types (features) have been stemmed, and recombined to consolidate features made equivalent because of stemming.

References

http://snowball.tartarus.org/

http://www.iso.org/iso/home/standards/language_codes.htm for the ISO-639 language codes

See Also

wordStem

Examples

# NOT RUN {
# example applied to tokens
txt <- c(one = "eating eater eaters eats ate",
         two = "taxing taxes taxed my tax return")
th <- tokens(txt)
tokens_wordstem(th)

# simple example
char_wordstem(c("win", "winning", "wins", "won", "winner"))

# example applied to a dfm
(origdfm <- dfm(txt))
dfm_wordstem(origdfm)

# }