使用字符串变量在 R 函数中传递多个变量信息

Question

这是一个可重现的例子

#install.packages("expss")
library("expss")
data(mtcars)
mtcars = apply_labels(mtcars,
                      mpg = "Miles/(US) gallon",
                      cyl = "Number of cylinders",
                      disp = "Displacement (cu.in.)",
                      hp = "Gross horsepower",
                      drat = "Rear axle ratio",
                      wt = "Weight (1000 lbs)",
                      qsec = "1/4 mile time",
                      vs = "Engine",
                      vs = c("V-engine" = 0,
                             "Straight engine" = 1),
                      am = "Transmission",
                      am = c("Automatic" = 0,
                             "Manual"=1),
                      gear = "Number of forward gears",
                      carb = "Number of carburetors"
)

mtcars %>%
  tab_cols(total(),vs,gear) %>%
  tab_cells(gear) %>% 
  tab_stat_cpct(total_row_position = "none", label = "col %") %>%
  tab_pivot(stat_position = "inside_rows")

根据我的情况，我想动态传递 tab_cols(total(),vs,gear) 中的变量信息。因此，为了便于使用，假设我想评估如下函数：

var1 <- "vs, gear"

mtcars %>%
  tab_cols(total(),var1) %>%
  tab_cells(gear) %>% 
  tab_stat_cpct(total_row_position = "none", label = "col %") %>%
  tab_pivot(stat_position = "inside_rows")

显然会出错！！我知道只适用于单个参数的惰性评估。因此尝试了很多在多个论坛上搜索但没有运气。

所以，一个好的方法可能是：

var1 <- "vs"
var2 <- "gear"
mtcars %>%
  tab_cols(total(),eval(parse(text = var1)),eval(parse(text = var2))) %>%
  tab_cells(gear) %>% 
  tab_stat_cpct(total_row_position = "none", label = "col %") %>%
  tab_pivot(stat_position = "inside_rows")

但我想用单个变量（它会以字符串或向量形式包含变量信息）来实现这一点，因为该变量可能存储超过 3 或 4 列信息。

Answer 1

文档 table_cols 说您可以传递列名列表。所以这似乎可以满足您的要求：

vars <- expression(list(vs, gear))

mtcars %>%
  tab_cols(total(), eval(vars)) %>%
  tab_cells(gear) %>% 
  tab_stat_cpct(total_row_position = "none", label = "col %") %>%
  tab_pivot(stat_position = "inside_rows")

Answer 2

expss中有一个特殊的参数传递工具：

var1 <- "vs, gear"
var_names = trimws(unlist(strsplit(var1, split = ","))) 

mtcars %>%
    tab_cols(total(), ..[(var_names)]) %>%
    tab_cells(gear) %>% 
    tab_stat_cpct(total_row_position = "none", label = "col %") %>%
    tab_pivot(stat_position = "inside_rows")

免责声明：我是 expss 包的作者。

使用字符串变量在 R 函数中传递多个变量信息

Passing multiple variable information inside R functions using string variable

r

lazy-evaluation

expss