# The pipe symbol, i.e. %>% that we will be discussing below
# is part of the magrittr package. You can install/load magrittr directly.
# Alternatively, magrittr is automatically installed/loaded with most of the
# tidyverse packages.
if(!require(magrittr)) {install.packages("magrittr");require(magrittr);}Loading required package: magrittr# For more info see:
#
# help(package="magrittr")`The %>% operator is used to send the output of one command into the into a 2nd commmand. Specifically, the info on the left side of the %>% is sent into the first argument of the function on the right hand side of the %>% See the example below.
# The following is code that does NOT use a "pipe".
x = seq(4,6)
rep(x, 3)[1] 4 5 6 4 5 6 4 5 6# The following code uses a "pipe", i.e. %>%, to send
# the info from the left of the %>% into the first argument
# of the function that appears on the right hand side
# of the %>%
seq(4, 6) %>% rep(3)[1] 4 5 6 4 5 6 4 5 6# We can extend this further
seq(4, 6) %>% rep(3) %>% sum()[1] 45# To make it easier to read, we can put each function
# call on a separate line.
seq(4, 6) %>%
rep(3) %>%
sum()[1] 45# Notice in the code above that the %>% appears at the end of
# each line. This is necessary to indicate to R that the command
# isn't finished yet.
# Without pipes, we could have coded the same thing using the
# following R code. This still works but the pipes make it easier
# to read and understand the code.
x = seq(4,6)
y = rep(x, 3)
sum(y)[1] 45If you want to send a value to an argument that is not the first, you can use the period as shown in the code below.
# define a vector of numbers
nums = c(1,3)
# This is without the pipe:
rep("hello", sum(nums))[1] "hello" "hello" "hello" "hello"# This is with the pipe. We use the . in the rep function to show
# where the output of the pipe should go.
sum(nums) %>%
rep("hello", .)[1] "hello" "hello" "hello" "hello"The %>% was and is still part of the magrittr package. The pipe was seen as such a useful tool that as of R version 4.1 “base-R” started to include its own version of the pipe. The base-R version of the pipe is |> while the magrittr version of the pipe is %>%
The pipe symbol that is now built into R (without needing to load the magrittr package) provides basic pipe functionality. However, if you want extra features (e.g. using the . to show where the data should be placed) then you still need to use the magrittr version of the pipe.
# The following is the new base-R version of the pipe
seq(4, 6) |>
rep(3) |>
sum()[1] 45# Unfortunately you cannot use |> to send the output to any location
# other than the 1st argument. For example:
nums = c(1,3)
# this doesn't work:
sum(nums) |> # using the new base-R pipe symbol |>
rep("hello", .) Error in eval(expr, envir, enclos): object '.' not found# but this does
sum(nums) %>% # using magrittr pipe symbol %>%
rep("hello", .) [1] "hello" "hello" "hello" "hello"