What does the %<>% operator mean in R? [closed]

问题

Closed. This question needs to be more focused. It is not currently accepting answers.

---

Want to improve this question? Update the question so it focuses on one problem only by editing this post.

Closed 3 years ago.

1. What does the %<>% operator do in R ?
2. What's the difference between using %<>% and <- ?
3. In what type of circumstances %<>% could be useful ?

回答1:

The help, ?magrittr::`%<>%`, answers all your questions, if you are refering to magrittr`s compound assignment pipe-operator:

[...] %<>% is used to update a value by first piping it into one or more rhs expressions, and then assigning the result. For example, some_object %<>% foo %>% bar is equivalent to some_object <- some_object %>% foo %>% bar. It must be the first pipe-operator in a chain, but otherwise it works like %>%.

So

library(magrittr)
set.seed(1);x <- rnorm(5)
x %<>% abs %>% sort
x
# [1] 0.1836433 0.3295078 0.6264538 0.8356286 1.5952808

is the same as

set.seed(1);x <- rnorm(5)
x <- sort(abs(x))
x
# [1] 0.1836433 0.3295078 0.6264538 0.8356286 1.5952808

来源：https://stackoverflow.com/questions/37772861/what-does-the-operator-mean-in-r