[SOLVED] Is it possible to add terms to the dictionaries of `lexicon` package?

Is it possible to add terms to the dictionaries of `lexicon` package?

The package sentimentr provides tools to calculate text polarity sentiment at the sentence level and optionally aggregate by rows or grouping variable. One of its functions, sentiment, approximates the sentiment (polarity) of text by sentence. In particular,

sentiment(text.var, polarity_dt = lexicon::hash_sentiment_jockers_rinker, ...)

text.var is the text variable, whereas polarity_dt is the dictionary provided by lexicon package. I would like to know whether it is possible to extend the set of terms in the lexicon dictionaries, by adding words (with their corresponding scores) to them.

Solution

You can. The sentiment tables are just data.tables. If you have words to add just create your own table and add these to the lexicon. See example below.

library(sentimentr)
library(data.table)

extra_terms <- data.table(x = c("word1", "word2"),
                          y = c(1.0, -1.0), 
                          key = "x")
# merge data with lexicon
my_lex <- merge(lexicon::hash_sentiment_jockers_rinker, extra_terms, by = c("x", "y"), all = TRUE)

sentiment(text.var, polarity_dt = my_lex, ...)