r - 如何根据R中具有相同字符串的两列的计算添加具有相同逻辑的多个新列

Question

我有一个如下所示的表格

data <- data.frame(A = c(1,2,3,4,5),
                   B = c(1,2,3,4,5),
                   C = c(11,12,13,14,15),
                   trans_A = c(NA,1,2,3,4),
                   trans_B = c(NA,1,2,3,4),
                   trans_C = c(NA,11,12,13,14))

我需要为这个数据框创建/添加多个新列，新名称为 difference_A、difference_B 等，逻辑 difference_A = A - trans_A 、difference_B = B - trans_B 等。如何在 R 中执行此操作？

我试过这个:

new_df[paste("difference", cols, sep = "_")]<- c(NA, new_df[cols]-new_df[paste("trans",cols,sep = "_")], na.rm=TRUE)

它给了我错误消息“列的重复下标”

Answer 1

一个 dplyr 和 purrr 解决方案可以是:

map(.x = names(select(data, -starts_with("trans_"))),
    ~ data %>%
     mutate(across(all_of(.x), .names = "difference_{col}") - across(all_of(paste0("trans_", .x))))) %>%
 reduce(full_join)

  A B  C trans_A trans_B trans_C difference_A difference_B difference_C
1 1 1 11      NA      NA      NA           NA           NA           NA
2 2 2 12       1       1      11            1            1            1
3 3 3 13       2       2      12            1            1            1
4 4 4 14       3       3      13            1            1            1
5 5 5 15       4       4      14            1            1            1