在 R 中的 across 中使用列名的子字符串答案

【问题标题】：Use substrings of column names in across in R在 R 中的 across 中使用列名的子字符串
【发布时间】：2022-12-03 21:16:32
【问题描述】：

I have the following tibble:

df <- tibble(
  x = c(5, 5),
  Column_1 = c(0.5, 0.5),
  Column_2 = c(0.75, 0.75))

I would like to create two new columns, which are the product of column x and Column_1 and x and Column_2 respectively. These columns should be named NewColumn_1 and NewColumn_2.

I tried the following code:

df <- mutate(df,
  across(starts_with(\"Column_\"),
              function(y) y * x,
              .names = paste0(\"NewColumn\", gsub(\"Column_\", \"\", \"{.col}\"))
        ))

However, this resulted in the following table:

x	Column_1	Column_2	NewColumnColumn_1	NewColumnColumn_2
5	0.5	0.75	2.5	3.75
5	0.5	0.75	2.5	3.75

The resulting columns are now named NewColumnColumn_1 and NewColumnColumn_2. Somehow creating a substring with gsub did not work. My desired output is:

x	Column_1	Column_2	NewColumn_1	NewColumn_2
5	0.5	0.75	2.5	3.75
5	0.5	0.75	2.5	3.75

Any ideas how I can elegantly solve this problem? In reality, the number of columns is variable, so I cannot hardcode 1 and 2 into my script.

Why dont you just paste New instead of NewColumn?

标签： r gsub across mutate r-glue

【解决方案1】：