sort_tf: Find High Frequency Terms
In chinese.misc: Miscellaneous Tools for Chinese Text Mining and More

Description Usage Arguments Details Value Examples

By inputting a matrix, or a document term matrix, or term document matrix, this function counts the sum of each term and output top n terms. The result can be messaged on the screen, so that you can manually copy them to other places (e. g., Excel).

1	sort_tf(x, top = 10, type = "dtm", todf = FALSE, must_exact = FALSE)

`x`	a matrix, or an object created by `corp_or_dtm` or by `tm::DocumentTermMatrix`, or `tm::TermDocumentMatrix`. Data frame is not allowed. If it is a matrix, the column names (if `type` is "dtm") or row names (if `type` is "tdm") is taken to be terms, see below. If the names are `NULL`, terms are set to "term1", "term2", "term3"...automatically.
`top`	a length 1 integer. As terms are in the decreasing order of the term frequency, this argument decides how many top terms should be returned. The default is 10. If the number of terms is smaller than `top`, all terms are returned. Sometimes the returned terms are more than `top`, see below.
`type`	should start with "D/d" representing document term matrix, or "T/t" representing term document matrix. It is only used when `x` is a matrix. The default is "dtm".
`todf`	should be `TRUE` or `FALSE`. If it is `FALSE` (default) terms and their frequencies will be pasted by "&" and messaged on the screen, nothing is returned. Otherwise, terms and frequencies will be returned as data frame.
`must_exact`	should be `TRUE` or `FALSE` (default). It decides whether the number of returned words should be equal to that specified by `top`. See Details.

Sometimes you may pick more terms than specified by top. For example, you specify to pick up the top 5 terms, and the frequency of the 5th term is 20. But in fact there are two more terms that have frequency of 20. As a result, sort_tf may pick up 7 terms. If you want the number is exactly 5, set must_exact to TRUE.

return nothing and message the result, or return a data frame.

require(tm)
x <- c(
  "Hello, what do you want to drink?", 
  "drink a bottle of milk", 
  "drink a cup of coffee", 
  "drink some water", 
  "hello, drink a cup of coffee")
dtm <- corp_or_dtm(x, from = "v", type = "dtm")
# Argument top is 5, but more than 5 terms are returned
sort_tf(dtm, top = 5)
# Set must_exact to TRUE, return exactly 5 terms
sort_tf(dtm, top=5, must_exact=TRUE)
# Input is a matrix and terms are not specified
m=as.matrix(dtm)
colnames(m)=NULL
mt=t(m)
sort_tf(mt, top=5, type="tdm")