Convert a dictionary from a different format into a quanteda dictionary, or check to see if an object is a dictionary.
as.dictionary(x, ...)
# S3 method for data.frame
as.dictionary(x, format = c("tidytext"), separator = " ", tolower = FALSE, ...)
is.dictionary(x)a object to be coerced to a dictionary object.
additional arguments passed to underlying functions.
input format for the object to be coerced to a
dictionary; current legal values are a data.frame with the fields
word and sentiment (as per the tidytext package)
the character in between multi-word dictionary values. This
defaults to " ".
if TRUE, convert all dictionary values to lowercase
as.dictionary returns a quanteda
object. This conversion function differs from the dictionary()
constructor function in that it converts an existing object rather than creates one from components or from a file.
is.dictionary returns TRUE if an object is a
quanteda
if (FALSE) {
data(sentiments, package = "tidytext")
as.dictionary(subset(sentiments, lexicon == "nrc"))
as.dictionary(subset(sentiments, lexicon == "bing"))
# to convert AFINN into polarities - adjust thresholds if desired
datafinn <- subset(sentiments, lexicon == "AFINN")
datafinn[["sentiment"]] <-
with(datafinn,
sentiment <- ifelse(score < 0, "negative",
ifelse(score > 0, "positive", "netural"))
)
with(datafinn, table(score, sentiment))
as.dictionary(datafinn)
dat <- data.frame(
word = c("Great", "Horrible"),
sentiment = c("positive", "negative")
)
as.dictionary(dat)
as.dictionary(dat, tolower = FALSE)
}
is.dictionary(dictionary(list(key1 = c("val1", "val2"), key2 = "val3")))
#> [1] TRUE
# [1] TRUE
is.dictionary(list(key1 = c("val1", "val2"), key2 = "val3"))
#> [1] FALSE
# [1] FALSE