How can I get cut2 to use commas?

Question

I am using the R function cut2 in the library Hmisc. I am giving it a vector of numbers which it then turns into equally sized intervals:

library(Hmisc)
vals = c(100, 1000, 2000, 3000, 40000, 50000, 60000)
vals_cut = cut2(vals, g=3)
vals_cut
[1] [  100, 3000) [  100, 3000) [  100, 3000) [ 3000,50000) [ 3000,50000) [50000,60000] [50000,60000]
Levels: [  100, 3000) [ 3000,50000) [50000,60000]

The problem arises when I try to use vals_cut on images when I share with others (e.g. on statistical graphics). People have found the output hard to read because a) the numbers do not have commas and b) there is not a space between the comma and the start of the second number.

I cannot find any options to cut2 which would modify the output in this way. Can anyone recommend an easy way to do this? Thanks.

Answer 1

Example:

library(Hmisc)
vals <-  c(100, 1000, 2000, 3000, 40000, 50000, 60000)
vals_cut = cut2(vals, g=3)
vals_cut

This basically works; you might want to make cosmetic adjustments.

library(stringr)
trans_level <- function(x,nsep=" to ") {
    n <- str_extract_all(x,"\\d+")[[1]]  ## extract numbers
    v <- format(as.numeric(n),big.mark=",",trim=TRUE) ## change format
    x <- as.character(x)
    paste0(
        substring(x, 1, 1),
        paste(v,collapse=nsep),
        substring(x, nchar(x), nchar(x)))  ## recombine
}
vals_cut2 <- vals_cut
levels(vals_cut2) <- sapply(levels(vals_cut),trans_level)
vals_cut2
[1] [100 to 3,000)     [100 to 3,000)     [100 to 3,000)     [3,000 to 50,000)  [3,000 to 50,000) [50,000 to 60,000] [50,000 to 60,000]
Levels: [100 to 3,000) [3,000 to 50,000) [50,000 to 60,000]

Answer 2

Here is a function just to format the levels of the intervals:

formatInterval <- function(x, intsep=", ") {
  if (length(x) > 1) {
    sapply(x, formatInterval, intsep=intsep)
  } else {
    makePretty <- function(z) {
      prettyNum(gsub("[^0-9]", "", z), big.mark=",")
    }
    bracket1 <- substr(x, 1, 1)
    bracket2 <- substr(x, nchar(x), nchar(x))
    x2 <- strsplit(x, ",")
    paste(bracket1,
          makePretty(x2[[1]][1]),
          intsep,
          makePretty(x2[[1]][2]),
          bracket2,
          sep="")    
  }
}

Now

> levels(vals_cut) <- formatInterval(levels(vals_cut))
> vals_cut
[1] [100, 3,000)     [100, 3,000)     [100, 3,000)     [3,000, 50,000)  [3,000, 50,000)  [50,000, 60,000]
[7] [50,000, 60,000]
Levels: [100, 3,000) [3,000, 50,000) [50,000, 60,000]

Or this might look nicer

> formatInterval(levels(vals_cut), intsep=" - ")
      [  100, 3000)       [ 3000,50000)       [50000,60000] 
    "[100 - 3,000)"  "[3,000 - 50,000)" "[50,000 - 60,000]"