R/tokens-methods.R
, R/tokens.R
as.tokens.Rd
Coercion functions to and from tokens objects, checks for whether an object is a tokens object, and functions to combine tokens objects.
# S3 method for tokens as.list(x, ...) # S3 method for tokens as.character(x, use.names = FALSE, ...) is.tokens(x) as.tokens(x, concatenator = "_", ...) # S3 method for spacyr_parsed as.tokens( x, concatenator = "/", include_pos = c("none", "pos", "tag"), use_lemma = FALSE, ... ) is.tokens(x)
x | object to be coerced or checked |
---|---|
... | additional arguments used by specific methods. For c.tokens, these are the tokens objects to be concatenated. |
use.names | logical; preserve names if |
concatenator | character between multi-word expressions, default is the underscore character. See Details. |
include_pos | character; whether and which part-of-speech tag to use:
|
use_lemma | logical; if |
as.list
returns a simple list of characters from a
tokens object.
as.character
returns a character vector from a
tokens object.
is.tokens
returns TRUE
if the object is of class
tokens, FALSE
otherwise.
as.tokens
returns a quanteda tokens object.
is.tokens
returns TRUE
if the object is of class
tokens, FALSE
otherwise.
The concatenator
is used to automatically generate dictionary
values for multi-word expressions in tokens_lookup()
and
dfm_lookup()
. The underscore character is commonly used to join
elements of multi-word expressions (e.g. "piece_of_cake", "New_York"), but
other characters (e.g. whitespace " " or a hyphen "-") can also be used.
In those cases, users have to tell the system what is the concatenator in
your tokens so that the conversion knows to treat this character as the
inter-word delimiter, when reading in the elements that will become the
tokens.
# create tokens object from list of characters with custom concatenator dict <- dictionary(list(country = "United States", sea = c("Atlantic Ocean", "Pacific Ocean"))) lis <- list(c("The", "United-States", "has", "the", "Atlantic-Ocean", "and", "the", "Pacific-Ocean", ".")) toks <- as.tokens(lis, concatenator = "-") tokens_lookup(toks, dict) #> Tokens consisting of 1 document. #> text1 : #> [1] "country" "sea" "sea" #>