按指定顺序对 R 数据帧进行排序

Question

假设我有（非常简单的例子）：

df <- data.frame(factor_name  = c("fac_Y", "fac_Y", "fac_Y", "fac_X", "fac_X", "fac_X", "fac_X", "fac_X", "fac_X"),
                 factor_level = c("cherry", "apple", "peach", 2, 1, 3, 4, 6, 8),
                 value        = c(1, 3, 2, 6, 3, 4, 1, 5, 2))

我需要根据factor_name 和factor_level 对df 进行排序不依赖字母/数字顺序（因为在我正在处理的更复杂的情况下，排序顺序是与这些事情完全无关）这样：

(i) factor_name 应该排序为(fac_X, fac_Y)

(ii) 在fac_X 内，factor_level 排序顺序应为(1, 2, 3, 4, 6, 8)

(iii) 在fac_Y 内，factor_level 排序顺序应为("apple", "peach", "cherry")

所以我需要手动提供有关我想要的顺序的信息（即上面的 (i)-(iii)），但我不确定该怎么做。

因此我希望我的输出是：

df_sorted <- data.frame(factor_name  = c("fac_X", "fac_X", "fac_X", "fac_X", "fac_X", "fac_X", "fac_Y", "fac_Y", "fac_Y"),
                        factor_level = c(1, 2, 3, 4, 6, 8, "apple", "peach", "cherry"),
                        value        = c(3, 6, 4, 1, 5, 2, 3, 2, 1))

有人可以帮忙吗？ 谢谢。

Answer 1

你可以在定义correct_order之后使用match。

library(dplyr)

correct_order <- c(1, 2, 3, 4, 6, 8, "apple", "peach", "cherry")
df %>% arrange(factor_name, match(factor_level, correct_order))

#  factor_name factor_level value
#1       fac_X            1     3
#2       fac_X            2     6
#3       fac_X            3     4
#4       fac_X            4     1
#5       fac_X            6     5
#6       fac_X            8     2
#7       fac_Y        apple     3
#8       fac_Y        peach     2
#9       fac_Y       cherry     1

您可以在基础 R order 中使用相同的：

df[with(df, order(factor_name, match(factor_level, correct_order))), ]

请注意，correct_order 应该首先具有 "fac_X" 的值，然后是 "fac_Y"，这并不重要。只要它们之间的值保持不变，它就可以按任何顺序排列。所以上面的答案会给出相同的输出：

correct_order <- c("apple", "peach", "cherry", 1, 2, 3, 4, 6, 8)

Answer 2

我们可以使用factor 指定levels

library(dplyr)
df %>% 
  arrange(factor_name, factor(factor_level,
      levels = c(1, 2, 3, 4, 6, 8, 'apple', 'peach', 'cherry')))
#   factor_name factor_level value
#1       fac_X            1     3
#2       fac_X            2     6
#3       fac_X            3     4
#4       fac_X            4     1
#5       fac_X            6     5
#6       fac_X            8     2
#7       fac_Y        apple     3
#8       fac_Y        peach     2
#9       fac_Y       cherry     1