使用case_when与dplyr跨接

Question

简单地说，我需要将一系列列中的值与一个“基线”列进行比较。当列中的值高于基线时，我需要使用基线值。当列中的值低于或等于基线时，我需要保留该值。下面是一个示例数据集（我的实际数据集要大得多）：

test <- structure(list(baseline = c(5, 7, 8, 4, 9, 1, 0, 46, 47), bob = c(7, 
11, 34, 9, 6, 8, 3, 49, 12), sally = c(3, 5, 2, 2, 6, 1, 3, 4, 
56), rita = c(6, 4, 6, 7, 6, 0, 3, 11, 3)), class = c("spec_tbl_df", 
"tbl_df", "tbl", "data.frame"), row.names = c(NA, -9L), spec = structure(list(
    cols = list(baseline = structure(list(), class = c("collector_double", 
    "collector")), bob = structure(list(), class = c("collector_double", 
    "collector")), sally = structure(list(), class = c("collector_double", 
    "collector")), rita = structure(list(), class = c("collector_double", 
    "collector"))), default = structure(list(), class = c("collector_guess", 
    "collector")), skip = 1), class = "col_spec"))

我当前的代码使用mutate_at()并且运行良好：

trial1 <- test %>% 
  mutate_at(
    vars('bob','sally', 'rita'),
    funs(case_when(
      . > baseline ~ baseline, 
      . <= baseline ~ .)))

但是当我试图更新它以反映DPLYR1.0中的跨（）时，我总是得到一个错误。以下是我的尝试：

trial2 <- test %>% 
  mutate(across(c(bob, sally, rita), 
                case_when(. > baseline ~ baseline, 
                          . <= baseline ~ .)))

你知道我做错了什么吗？case_when()是否适用于交叉？

Answer 1

我们可以使用~指定匿名函数/lambda函数调用

library(dplyr)
test %>% 
   mutate(across(c(bob, sally, rita), 
             ~ case_when(. > baseline ~ baseline, 
                       . <= baseline ~ .)))

-输出

# A tibble: 9 x 4
#  baseline   bob sally  rita
#     <dbl> <dbl> <dbl> <dbl>
#1        5     5     3     5
#2        7     7     5     4
#3        8     8     2     6
#4        4     4     2     4
#5        9     6     6     6
#6        1     1     1     0
#7        0     0     0     0
#8       46    46     4    11
#9       47    12    47     3

或使用.funs参数

test %>% 
        mutate(across(c(bob, sally, rita), 
                  .funs = case_when(. > baseline ~ baseline, 
                            . <= baseline ~ .)))

函数/lambda列表，例如list（mean=mean,n_miss=~sum(is.na(.x))

另外，我们可以使用case_when代替pmin

test %>% 
    mutate(across(c(bob, sally, rita), ~ pmin(baseline, .)))

-输出

# A tibble: 9 x 4
#  baseline   bob sally  rita
#     <dbl> <dbl> <dbl> <dbl>
#1        5     5     3     5
#2        7     7     5     4
#3        8     8     2     6
#4        4     4     2     4
#5        9     6     6     6
#6        1     1     1     0
#7        0     0     0     0
#8       46    46     4    11
#9       47    12    47     3