Properly using reprex package when generating examples that load libraries

Question

I would like to use a reprex package when generating an answer/question¹ that utilises multiple packages. Say I want to provide the following answer

library("gdata")
dfA <- data.frame(colA = c(1, 2), colB = c(3, 4))
ls()
mv(from = "dfA", to = paste0("df", "B"))
ls()

If I pass this code directly to reprex the output will be as follows:

library("gdata")
#> gdata: read.xls support for 'XLS' (Excel 97-2004) files ENABLED.
#> 
#> gdata: Unable to load perl libaries needed by read.xls()
#> gdata: to support 'XLSX' (Excel 2007+) files.
#> 
#> gdata: Run the function 'installXLSXsupport()'
#> gdata: to automatically download and install the perl
#> gdata: libaries needed to support Excel XLS and XLSX formats.
#> 
#> Attaching package: 'gdata'
#> The following object is masked from 'package:stats':
#> 
#>     nobs
#> The following object is masked from 'package:utils':
#> 
#>     object.size
#> The following object is masked from 'package:base':
#> 
#>     startsWith
dfA <- data.frame(colA = c(1, 2), colB = c(3, 4))
ls()
#> [1] "dfA"
mv(from = "dfA", to = paste0("df", "B"))
ls()
#> [1] "dfB"

^{Created on 2022-03-23 by the reprex package (v2.0.1)}

There is a lost of irrelevant info related to the package load. An alternative is to suppress package startup messages:

suppressPackageStartupMessages(library("gdata"))
dfA <- data.frame(colA = c(1, 2), colB = c(3, 4))
ls()
#> [1] "dfA"
mv(from = "dfA", to = paste0("df", "B"))
ls()
#> [1] "dfB"

^{Created on 2022-03-23 by the reprex package (v2.0.1)}

The above reprex output is generated via:

library("reprex")
reprex(x = {
    suppressPackageStartupMessages(library("gdata"))
    dfA <- data.frame(colA = c(1, 2), colB = c(3, 4))
    ls()
    mv(from = "dfA", to = paste0("df", "B"))
    ls()

}, venue = "so")

Question

Is there a cleaner way to do this? Reprex offers tidyverse_quiet but I'm wondering if there is an intelligent way to "stretch" that argument to apply to multiple packages? In a hypothetical answer that loads multiple packages, I would like to avoid writing suppressPackageStartupMessages a number of times just to suppress unnecessary outputs.

Writing package::function may be onerous when calling multiple functions from various packages.

¹For reference, I started thinking on that that after contributing an answer to this question.

score 2 · Accepted Answer · answered Mar 23 '22 at 12:31

Another option to consider is to use knitr chunk options inside the reprex. Obviously, these would apply to all code within the chunk although you could use multiple chunks for more control.

reprex(x = {
  #+ chunk1, message = FALSE
  library("gdata")
  dfA <- data.frame(colA = c(1, 2), colB = c(3, 4))
  ls()
  mv(from = "dfA", to = paste0("df", "B"))
  ls()
  }, venue = "so")

Which gives:

library("gdata")
dfA <- data.frame(colA = c(1, 2), colB = c(3, 4))
ls()
#> [1] "dfA"
mv(from = "dfA", to = paste0("df", "B"))
ls()
#> [1] "dfB"

^{Created on 2022-03-23 by the reprex package (v2.0.1)}

score 1 · Answer 2 · answered Mar 23 '22 at 12:09

You don't need to run suppressPackageStartupMessages more than once. You can do

suppressPackageStartupMessages({
  library(gdata)
  library(tidyverse)
})
#> Warning: package 'tidyr' was built under R version 4.1.2
#> Warning: package 'dplyr' was built under R version 4.1.2

^{Created on 2022-03-23 by the reprex package (v2.0.1)}

You'll still see warnings, but most of the junk is suppressed.

For SO, you could shorten this to

suppressMessages({
  library(gdata)
  library(tidyverse)
})

I wouldn't do this routinely, because maybe some packages have useful messages. It might also give newbies the wrong idea and have them using it in their own code, missing out on those messages.

If you want somewhat less suppression, you can use

library(gdata, quietly = TRUE)
library(tidyverse, quietly = TRUE)

Properly using reprex package when generating examples that load libraries

Question

2 Answers2