如何在R语言中将函数参数指定为变量名以实现对象重命名？

Hey there! As someone moving from SAS macros to R, I totally get wanting to replicate that dynamic variable renaming logic. Let's fix your current function and build a solution that does exactly what you need—whether you're working with global variables or (more commonly in R) columns in a data frame.

First, Why Your Original Function Isn't Working #

Your rename.fun has two key issues:

1. When you use assign('pred', rai), you're hardcoding the string "pred" instead of using the actual variable name you passed in (like "k2e_cat2").
2. assign() defaults to creating the variable in the function's internal environment, not the global environment where your original variables live. So even if it worked, the new variable wouldn't show up where you need it.

Solution 1: Rename a Single Global Variable #

If you really need to rename standalone global variables (like your initial example), here's a corrected function. Note that we'll pass variable names as strings (since R needs to know the name of the variable, not just its value):

rename_fun <- function(original_var_name, new_var_name) {
  # Grab the value of the original variable from the global environment
  original_value <- get(original_var_name, envir = globalenv())
  # Create the new variable in the global environment with the desired name
  assign(new_var_name, original_value, envir = globalenv())
  # Optional: Return the new variable name to confirm it worked
  cat(paste("Created variable:", new_var_name, "\n"))
  return(new_var_name)
}

Call it like this (using strings for the variable names):

# Assume k2e already exists in your environment
rename_fun("k2e", "k2e_cat2")

Solution 2: Batch Rename Variables with _cat2 Suffix #

To replicate your SAS macro's batch functionality (adding _cat2 to a list of variables), we can wrap the logic in a loop:

batch_rename_cat2 <- function(var_names) {
  new_var_names <- paste0(var_names, "_cat2")
  for(i in seq_along(var_names)) {
    original_value <- get(var_names[i], envir = globalenv())
    assign(new_var_names[i], original_value, envir = globalenv())
  }
  cat(paste("Created variables:", paste(new_var_names, collapse = ", "), "\n"))
  return(new_var_names)
}

Use it with a list of variable names:

# Rename k2e, var1, and var2 all at once
batch_rename_cat2(c("k2e", "var1", "var2"))

Bonus: Rename Data Frame Columns (More R-idiomatic) #

In R, we almost always store data in data frames (like SAS datasets) instead of standalone variables. If that's your actual use case, here's how to replicate your SAS macro's logic for data frame columns using dplyr (a popular R package for data manipulation):

First, install/load dplyr if you haven't:

install.packages("dplyr")
library(dplyr)

Single Column Rename

# Rename the k2e column to k2e_cat2 in your data frame (e.g., df)
df <- df %>% rename(k2e_cat2 = k2e)

Batch Rename Columns with _cat2 Suffix

# List of columns you want to rename
cols_to_rename <- c("k2e", "var1", "var2")

# Add _cat2 suffix to all specified columns
df <- df %>% 
  rename_with(~paste0(., "_cat2"), all_of(cols_to_rename))

This is the approach most R users would recommend, since it keeps your data organized in a single data frame (instead of cluttering your global environment with lots of standalone variables).

内容的提问来源于stack exchange，提问作者Rob Tala