RoyalTS's questions

我试图用这个典型例子来说明卷曲运算符的工作原理

mean_by <- function(data, by, var) {
  data %>%
    dplyr::group_by({{ by }}) %>%
    dplyr::summarise(avg = mean({{ var }}, na.rm = TRUE))
}

mtcars %>% mean_by(by = cyl, var = disp)

并通过向分组添加一个额外的变量来修改它。唉，我可能永远都不明白这个操作符到底做了什么；我尝试做的事情如下

mean_by <- function(data, by, var) {
  data %>%
    dplyr::group_by({{ c(by, hp) }}) %>%
    dplyr::summarise(avg = mean({{ var }}, na.rm = TRUE))
}

mtcars %>% mean_by(by = cyl, var = disp)

显然不起作用