R重命名函数中传递的列 [英] R renaming passed columns in functions

问题描述

我一直在搜索此文件，并找到了此链接有助于重命名函数中传递的列（ [，column_name] 代码实际上使 my_function1 工作搜寻了一段时间之后，是否可以使用管道运算符重命名函数中数据框中的列？

I have been searching this and have found this link to be helpful with renaming passed columns from a function (the [,column_name] code actually made my_function1 work after I had been searching for a while. Is there a way to use the pipe operator to rename columns in a dataframe within a function?

我的尝试显示在 my_function2 ，但它给了我一个错误：必须重命名所有重命名的参数或错误：未知变量：col2 。我猜是因为我没有指定 col2 属于什么。

My attempt is shown in my_function2 but it gives me an Error: All arguments to rename must be named or Error: Unknown variables: col2. I am guessing because I have not specified what col2 belongs to.

此外，还有一种方法可以将关联的参数传递给函数，例如col1和new_col1，以便您可以将要替换的列名和要替换的列名相关联。

Also, is there a way to pass associated arguments into the function, like col1 and new_col1 so that you can associated the column name to be replaced and the column name that is replacing it. Thanks in advance!

library(dplyr)

my_df = data.frame(a = c(1,2,3), b = c(4,5,6), c = c(7,8,9))

my_function1 = function(input_df, col1, new_col1) {
  df_new = input_df
  df_new[,new_col1] = df_new[,col1]
  return(df_new)
}
temp1 = my_function1(my_df, "a", "new_a")

my_function2 = function(input_df, col2, new_col2) {
  df_new = input_df %>%
    rename(new_col2 = col2)
  return(df_new)
}

temp2 = my_function2(my_df, "b", "new_b")

推荐答案

在 @MatthewPlourde对类似问题的回答，我们可以这样做：

my_function3 = function(input_df, cols, new_cols) { 
  rename_(input_df, .dots = setNames(cols, new_cols)) 
}

# example
my_function3(my_df, "b", "new_b")
#   a new_b c
# 1 1     4 7
# 2 2     5 8
# 3 3     6 9

许多dplyr函数的知识较少名称以 _ 结尾的n个变体。使您可以更编程地使用软件包。一种模式是...

Many dplyr functions have less-known variants with names ending in _. that allow you to work with the package more programmatically. One pattern is...

DF %>% dplyr_fun(arg1 = val1, arg2 = val2, ...)
# becomes
DF %>% dplyr_fun_(.dots = list(arg1 = "val1", arg2 = "val2", ...))

这在某些情况下对我有用，其中 val * 只是列名。键入 vignette（ nse）时弹出的文档中包含更复杂的模式和技术，但我不太了解它们。

This has worked for me in a few cases, where the val* are just column names. There are more complicated patterns and techniques, covered in the document that pops up when you type vignette("nse"), but I do not know them well.

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