R函数比较列

Question

In R language I would like to create a function to view selected columns for comparison in the Viewer. Assuming my dataframe is df1:

compare_col <- function(x){
  select(df1, x) %>%
    View()
}

If I define the function by x, I can only put input 1 column.

compare_col <- function(x)

compare_col("col_1")

Only if I define the function by say x,y, then can I input in 2 columns.

compare_col <- function(x, y)

compare_col("col_1", "col_2")

How can I create a function that is dynamic enough to input in any no. of columns?

Answer 1

You can use the rlang package to achieve this. This will allow you to input a string of column names using the syms and !!! operator which will splice and evaluate in the given environment dynamically as you require.

library(dplyr)
#library(rlang)
compare_col <- function(x){
  df1 %>% select(!!! syms(x)) %>%
    View()
}
compare_col(c("col1", "col2"))

Answer 2

刚刚意识到，我实际需要做的就是在调用函数时向量化输入。

compare_col(c("col1", "col2"))