Apply a Snowball stemming algorithm to a vector of input terms, x
,
returning the result in a character vector of the same length with the
same names.
The algorithm
argument specifies the stemming algorithm. Valid choices
include the following:
"ar"
("arabic"
),
"da"
("danish"
),
"de"
("german"
),
"en"
("english"
),
"es"
("spanish"
),
"fi"
("finnish"
),
"fr"
("french"
),
"hu"
("hungarian"
),
"it"
("italian"
),
"nl"
("dutch"
),
"no"
("norwegian"
),
"pt"
("portuguese"
),
"ro"
("romanian"
),
"ru"
("russian"
),
"sv"
("swedish"
),
"ta"
("tamil"
),
"tr"
("turkish"
),
and "porter"
.
Setting algorithm = NULL
gives a stemmer that returns its input
unchanged.
The function only stems single-word terms of kind "letter"; it leaves
other inputs (multi-word terms, and terms of kind "number", "punct", and
"symbol") unchanged.
The Snowball stemming library
provides the underlying implementation. The wordStem
function from
the SnowballC package provides a similar interface, but that function
applies the algorithm to all input terms, regardless of the kind of the term.