使用 dplyr 查找配对列的差异

Question

set.seed(3)
library(dplyr)
dat <- tibble(Measure = c("Height","Weight","Width","Length"),
             AD1_1= rpois(4,10),
             AD1_2= rpois(4,9),
             AD2_1= rpois(4,10),
             AD2_2= rpois(4,9),
             AD3_1= rpois(4,10),
             AD3_2= rpois(4,9),
             AD4_1= rpois(4,10),
             AD4_2= rpois(4,9),
             AD5_1= rpois(4,10),
             AD5_2= rpois(4,9),
             AD6_1= rpois(4,10),
             AD6_2= rpois(4,9))

假设我有这样的数据。我希望计算每个 AD 的差异，并与下划线数字配对，即 AD1diff、AD2diff、AD3diff。

而不是写作

dat %>%
mutate(AD1diff = AD1_1 - AD1_2,
       AD2diff = AD2_1 - AD2_2,
...)

写这个的有效方法是什么？

Answer 1

一种dplyr选择可能是：

dat %>%
 mutate(across(ends_with("_1"), .names = "{col}_diff") - across(ends_with("_2"))) %>%
 rename_with(~ sub("_\\d+", "", .), ends_with("_diff"))

  Measure AD1_1 AD1_2 AD2_1 AD2_2 AD3_1 AD3_2 AD4_1 AD4_2 AD5_1 AD5_2 AD6_1 AD6_2 AD1_diff AD2_diff AD3_diff AD4_diff AD5_diff AD6_diff
  <chr>   <int> <int> <int> <int> <int> <int> <int> <int> <int> <int> <int> <int>    <int>    <int>    <int>    <int>    <int>    <int>
1 Height      6    10    10     3    12     8     7     5     7     5     8     9       -4        7        4        2        2       -1
2 Weight      8     9    13     6    14     7     8     7    13    11    10     9       -1        7        7        1        2        1
3 Width      10     9    11     5    12     8     7    11     9     5     5     6        1        6        4       -4        4       -1
4 Length      8     9     8     7     8    13     8     7     6    11    14     6       -1        1       -5        1       -5        8