我想dplyr::group_by在另一個函數中使用函數，但是我不知道如何將參數傳遞給該函數。有人可以提供一個有效的例子嗎？library(dplyr)data(iris)iris %.% group_by(Species) %.% summarise(n = n()) # ## Source: local data frame [3 x 2]##      Species  n## 1  virginica 50## 2 versicolor 50## 3     setosa 50mytable0 <- function(x, ...) x %.% group_by(...) %.% summarise(n = n())mytable0(iris, "Species") # OK## Source: local data frame [3 x 2]##      Species  n## 1  virginica 50## 2 versicolor 50## 3     setosa 50mytable1 <- function(x, key) x %.% group_by(as.name(key)) %.% summarise(n = n())mytable1(iris, "Species") # Wrong!# Error: unsupported type for column 'as.name(key)' (SYMSXP)mytable2 <- function(x, key) x %.% group_by(key) %.% summarise(n = n())mytable2(iris, "Species") # Wrong!# Error: index out of bounds