基于quosure命名新变量

Question

我正在尝试编写一个自定义函数,它将根据预定义变量向量(例如vector_heavy)的值计算新变量,然后根据提供给函数的参数(例如,custom_name)命名新变量.

这个变量命名是我的技能失败的地方.任何帮助是极大的赞赏.

library(tidyverse)

vector_heavy <- quos(disp, wt, cyl)

cv_compute <- function(data, cv_name, cv_vector){
  cv_name <- enquo(cv_name)
  data %>% 
    rowwise() %>% 
    mutate(!!cv_name = mean(c(!!!cv_vector), na.rm = TRUE)) %>% 
    ungroup()
}

d <- cv_compute(mtcars, cv_name = custom_name, cv_vector = vector_heavy)

我的错误消息是:

Error: unexpected '=' in:
"    rowwise() %>% 
    mutate(!!cv_name ="

删除!!之前cv_name的mutate()将导致一个函数计算一个字面命名的新变量cv_name,并忽略custom_name我作为参数包含的内容.

cv_compute <- function(data, cv_name, cv_vector){
  cv_name <- enquo(cv_name)
  data %>% 
    rowwise() %>% 
    mutate(cv_name = mean(c(!!!cv_vector), na.rm = TRUE)) %>% 
    ungroup() 
}

我怎样才能使用这个函数来利用custom_name我提供的参数cv_name？

Answer 1

你需要在里面使用:=帮助器mutate.您还需要quo_name将输入转换为字符串.

该mutate那么你的函数的线看起来像

mutate(!!quo_name(cv_name) := mean(c(!!!cv_vector), na.rm = TRUE))

完整的:

cv_compute <- function(data, cv_name, cv_vector){
     cv_name <- enquo(cv_name)
     data %>% 
          rowwise() %>% 
          mutate(!!quo_name(cv_name) := mean(c(!!!cv_vector), na.rm = TRUE)) %>% 
          ungroup()
}

cv_compute(mtcars, cv_name = custom_name, cv_vector = vector_heavy)

    mpg   cyl  disp    hp  drat    wt  qsec    vs    am  gear  carb custom_name
  <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>       <dbl>
1  21.0     6   160   110  3.90 2.620 16.46     0     1     4     4    56.20667
2  21.0     6   160   110  3.90 2.875 17.02     0     1     4     4    56.29167
3  22.8     4   108    93  3.85 2.320 18.61     1     1     4     1    38.10667
4  21.4     6   258   110  3.08 3.215 19.44     1     0     3     1    89.07167
5  18.7     8   360   175  3.15 3.440 17.02     0     0     3     2   123.81333
6  18.1     6   225   105  2.76 3.460 20.22     1     0     3     1    78.15333