遍历dplyr中的列？

Question

df <- data.frame(col1 = rep(1, 15),
                  col2 = rep(2, 15),
                  col3 = rep(3, 15),
                  group = c(rep("A", 5), rep("B", 5), rep("C", 5)))

for(col in c("col1", "col2", "col3")){
   filt.df <- df %>%
     filter(group == "A") %>%
     select(group, col)
     # do other things, like ggplotting
 }

错误：所有 select() 输入必须解析为整数列位置。以下不要： * col

如何使用 迭代特定的列向量dplyr？我知道我会df[[col]]在baseR 中使用类似的东西，但我不熟悉如何在dplyr.

Answer 1

这应该有效。我使用 select_() 函数

library(dplyr)

df <- data.frame(col1 = rep(1, 15),
                 col2 = rep(2, 15),
                 col3 = rep(3, 15),
                 group = c(rep("A", 5), rep("B", 5), rep("C", 5)))

for(col in c("col1", "col2", "col3")){
  filt.df <- df %>%
    filter(group == "A") %>%
    select_(.dots = c('group', col))
  # do other things, like ggplotting
  print(filt.df)
}