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# New features in R 4.2.0

Author: Colin Gillespie

Published: April 1, 2022

# R-4.2.0 is due to be released!

Another year has passed, which means an updated version of R is due to be released - R version 4.2.0. As usual there have been many changes and improvements over the last year. This blog post only picks out a tiny handful, but there are dozens of smaller changes and bug fixes that can be found in the changelog.

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## Pipe updates

The native pipe |> was introduced in R 4.1.0. This release has introduced the _ that can be used as a placeholder in a named argument. For example,

# This works in R 4.2
mtcars |>
lm(mpg ~ disp, data = _)


Side note: some of the older R users amongst us, still remember when _ was used as an assignment operator!

## Improved help page

The HTML help system has a few new features:

• LaTeX-like mathematics can be typeset using either KaTeX or MathJax, usage and example code is highlighted using Prism.
• Dynamic help for examples and code demos using {knitr}.

The HTML help system now uses HTML5 (via PR#18149). What this means to everyday R users is that the help package looks a lot nicer

The examples can now be easily run using the Run Examples button

## if and while statements

Calling while() or if() statements with a condition of length greater than one gives an error rather than a warning.

if (1:2 == 1) do_something()
# Error in if (1:2 == 1) do_something() : the condition has length > 1


This is clearly a good thing, as when the length of the condition is greater than one, this is almost certainly an error. If you are using older versions of R, you can set _R_CHECK_LENGTH_1_CONDITION_ to true in your .Renviron to get the same effect.

## Changes to Windows

There are quite few changes to Windows, in particular

• Support for 32-bit builds has been dropped.
• UTF-8 locales are used where available.
• The default personal library on Windows, folder R\win-library\x.y where x.y stands for R release x.y.z, is now a subdirectory of local application data directory (usually a hidden directory C:\Users\username\AppData\Local).

## Data frames gain a new method

The as.vector() function gains an S3 data frame method which returns a simple list.

#> as.vector(mtcars[1:5,])
#$mpg #[1] 21.0 21.0 22.8 21.4 18.7 # #$cyl
#[1] 6 6 4 6 8
#
#\$disp
#[1] 160 160 108 258 360


This is a breaking change; in previous versions of R, as.vector() just returned the data frame.

## Changes to logical functions

This was part of R 4.2.0, but has been bumped to R-devel as there are around 200 packages that have to be updated.

Similar to the if() and while() statements, the logical functions, && and ||, now give a warning when one of the comparisons has a length greater than one:

1:2 && 1
# [1] TRUE
# Warning message:
# In 1:2 && 1 : 'length(x) = 2 > 1' in coercion to 'logical(1)'


In future versions, this will become an error.

## Trying the latest version out for yourself

The rocker project takes away the pain of installing the latest version. If you have docker installed, then simply use the devel version:

docker run --rm -ti rocker/r-ver:devel


If you want to use RStudio as well, then run

docker run -e PASSWORD=<PASSWORD> -p 8787:8787 rocker/rstudio:devel


## See also

Do you have some nostalgia for previous versions of R? If so, check out our previous blog posts: