Question

What R packages and functions are used in text cleaning process?

Answer 1

You need to use stringr packages.
install using this command
install.packages("stringr", dependencies = TRUE)
library(stringr).

And you can use the following function to cleaning text.

Clean_String <- function(str){
    # Lowercase
    tem <- tolower(str)
    # Remove everything that is not a number or letter (may want to keep more 
    tem <- stringr::str_replace_all(tem,"[^a-zA-Z\\s]", " ")
    # Shrink down to just one white space
    tem <- stringr::str_replace_all(tem,"[\\s]+", " ")
    # Split it
    tem <- stringr::str_split(tem, " ")[[1]]
    # Get rid of trailing "" if necessary
    i <- which(tem == "")
    if(length(indexes) > 0){
      tem <- tem[-i]
    } 
    return(tem)
}