How to multiply with %<>% (from magrittr package) in R?

Question

Let's assign value to a variable:

thisIsANumberVariable <- 3

library(magrittr)
thisIsANumberVariable %<>% +5 #adds 5 to thisIsANumberVariable
thisIsANumberVariable
[1] 8
thisIsANumberVariable %<>% *6 # Should multiply thisIsANumberVariable by 8, but instead:
Error: unexpected '*' in "thisIsANumberVariable %<>% *"

Is there a way to multiply and assign simultaneously with %<>%?

Answer 1

One option would be to use `*`() or the multiply_by alias (see eg ?magrittr::multiply_by for a list of available aliases):

thisIsANumberVariable <- 3

library(magrittr)

thisIsANumberVariable %<>% +5

thisIsANumberVariable
#> [1] 8

thisIsANumberVariable %<>% `*`(5)

thisIsANumberVariable
#> [1] 40

thisIsANumberVariable %<>% multiply_by(5)

thisIsANumberVariable
#> [1] 200

Answer 2

The magrittr package provides a variety of aliases to use in place of symbols. These include add , multiply_by and others. See the Alias section in the vi.nette which is obtained via the R code vi.nette("magrittr") and to see them all try entering this:

help("extract", package = "magrittr")

For example, we can write

library(magrittr)

x <- 3
x %<>% multiply_by(5)
x
## [1] 15