Dplyr中的for循环

Question

我有一个代码如下。 首先，代码应该基于dplyr::arrange(desc(sum.total))然后dplyr::arrange(desc(sum.mpg)) ，然后作为结果我想要一个数据帧/数据表。 提前谢谢了

head(mtcars)

my.mtcars <- mtcars %>%
  dplyr::group_by(gear)%>%
  dplyr::summarise(
    sum.total = n(),
    sum.mpg = sum(mpg))%>%
  dplyr::arrange(desc(sum.total)) # Run me first
  #dplyr::arrange(desc(sum.mpg))  # Second Dont run the line above but this

预期答案

#with dplyr::arrange(desc(sum.total))
gear sum.total sum.mpg

1     3        15    242.
2     4        12    294.
3     5         5    107.
#with dplyr::arrange(desc(sum.mpg))
gear sum.total sum.mpg

1     4        12    294.
2     3        15    242.
3     5         5    107.

Answer 1

my.mtcars <- mtcars %>%
  dplyr::group_by(gear)%>%
  dplyr::summarise(
    sum.total = n(),
    sum.mpg = sum(mpg)
lapply(c('sum.total', 'sum.mpg'), function(var) arrange(my.mtcars, desc(.data[[var]])))