Remove whitespace from formatted flextable columns

Question

I want to convert this data to a flextable, format the columns, and save as an image for reporting purposes:

library(flextable)
library(dplyr)

df = data.frame(col1 = c(10,1,0,0.1,-0.5,-100, NA),
                col2 = c(1,1,0,0.1,-0.5,-1, NA),
                col3 = c(10,1,0,0.1,-0.5,-10000.90, NA),
                col4 = c(10,1,0,0.1,-0.5,-100, NA)
)

formater_for_ft = function(x){
    ifelse(x < 0, paste0("(",format(round(as.numeric(abs(x)), 1), 
                                    nsmall=1, big.mark=","),")"),
           ifelse(x == 0, paste("-"),
                  ifelse(is.na(x), "",
                         ifelse(x > 100,
                                format(round(as.numeric(x), 1), nsmall=1, big.mark=","),
                                format(round(as.numeric(x), 1), nsmall=1)))))
  }

ft = df %>% 
  flextable() %>%
  set_formatter(col1 = function(x) formater_for_ft(x)) %>%
  set_formatter(col2 = function(x) formater_for_ft(x)) %>%
  set_formatter(col3 = function(x) formater_for_ft(x)) %>%
  set_formatter(col4 = function(x) formater_for_ft(x))
ft
save_as_image(ft,
              path = "/home/app/mre.png",
              zoom = 3 ,
              webshot = "webshot2")

This looks almost acceptable in the viewer:

But the saved image there is leading whitespaces in the 4th row of the 1st, 3rd and 4th columns:

I would like it to look like the 4th row and 2nd column

Is there something that can be done to solve this issue?

for reference I am running in a docker container using rocker/verse

Answer 1

The problem is that your function is leaving a space when it substitutes the negative signs. Use the str_remove_all function from the stringr package to remove all spaces. Example:

df <-  data.frame(col1 = c(10,1,0,0.1,-0.5,-100, NA),
                col2 = c(1,1,0,0.1,-0.5,-1, NA),
                col3 = c(10,1,0,0.1,-0.5,-10000.90, NA),
                col4 = c(10,1,0,0.1,-0.5,-100, NA)
)


formater_for_ft = function(x){
  ifelse(x < 0, 
         stringr::str_remove_all(                            # Here
    paste0("(",format(round(as.numeric(abs(x)), 1), 
                      nsmall=1, big.mark=","),")"), 
    " "),                                                    # Here
    ifelse(x == 0, paste("-"),
                ifelse(is.na(x), "",
                       ifelse(x > 100,
                              format(round(as.numeric(x), 1), nsmall=1, big.mark=","),
                              format(round(as.numeric(x), 1), nsmall=1)))))
}


ft <-  df %>% 
  flextable() %>%
  set_formatter(col1 = function(x) formater_for_ft(x)) %>%
  set_formatter(col2 = function(x) formater_for_ft(x)) %>%
  set_formatter(col3 = function(x) formater_for_ft(x)) %>%
  set_formatter(col4 = function(x) formater_for_ft(x))
  
ft
save_as_image(ft,
              path = "mre.png",
              zoom = 3 ,
              webshot = "webshot2")

Outputs: