将管道运算符%&gt；%与colames()&lt；- [英] Use pipe operator %>% with replacement functions like colnames()<-

问题描述

如何使用管道运算符通过管道导入colnames()<-这样的替换函数？

我尝试这样做：

library(dplyr)
averages_df <- 
   group_by(mtcars, cyl) %>%
   summarise(mean(disp), mean(hp))
colnames(averages_df) <- c("cyl", "disp_mean", "hp_mean")
averages_df

# Source: local data frame [3 x 3]
# 
#   cyl disp_mean   hp_mean
# 1   4  105.1364  82.63636
# 2   6  183.3143 122.28571
# 3   8  353.1000 209.21429

但理想情况下应该是这样的：

averages_df <- 
  group_by(mtcars, cyl) %>%
  summarise(mean(disp), mean(hp)) %>%
  add_colnames(c("cyl", "disp_mean", "hp_mean"))

有没有一种方法可以做到这一点，而不需要每次都编写专门的函数？

这里的答案是一个开始，但不完全是我的问题：Chaining arithmetic operators in dplyr

推荐答案

您可以使用colnames<-或setNames(感谢@David Arenburg)

group_by(mtcars, cyl) %>%
  summarise(mean(disp), mean(hp)) %>%
  `colnames<-`(c("cyl", "disp_mean", "hp_mean"))
  # or
  # `names<-`(c("cyl", "disp_mean", "hp_mean"))
  # setNames(., c("cyl", "disp_mean", "hp_mean")) 

#   cyl disp_mean   hp_mean
# 1   4  105.1364  82.63636
# 2   6  183.3143 122.28571
# 3   8  353.1000 209.21429

或从magrittr中选择一个Alias(set_colnames)：

library(magrittr)
group_by(mtcars, cyl) %>%
  summarise(mean(disp), mean(hp)) %>%
  set_colnames(c("cyl", "disp_mean", "hp_mean"))

dplyr::rename如果您只(重新)命名许多列中的几个(需要同时写入旧名称和新名称，请参阅@Richard Scriven的答案)，可能会更方便。

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