使用本机管道进行 R 条件评估 |>

Question

我们如何有条件地评估本机 R

|>

管道中的步骤？

这篇文章展示了如何使用magrittr

%>%

管道来做到这一点。

library(dplyr)

do_thing = TRUE

# Works with magrittr syntax leading into the `{ }` expression.
x <- iris %>%
  { if (do_thing) mutate(., Sepal.Length = Sepal.Length + 100) else . } |> 
  select(Sepal.Length)

# Errors with native pipe leading into the `{ }`
# NB: the placeholder after `mutate(_` is updated
# Error in { : 
#  function '{' not supported in RHS call of a pipe (<input>:2:3)
x <- iris |> 
  { if (do_thing) mutate(_, Sepal.Length = Sepal.Length + 100) else . } |> 
  select(Sepal.Length)