如何根据特定顺序对字符向量进行排序？答案

【问题标题】：How to sort a character vector according to a specific order?如何根据特定顺序对字符向量进行排序？
【发布时间】：2013-06-10 19:09:10
【问题描述】：

我有一个看起来像

的字符向量

c("white","white","blue","green","red","blue","red")

还有一个特定的顺序，比如

c("red","white","blue","green")

。我想根据第二个向量的顺序对第一个向量进行排序，以获得以下向量：c("red","red","white","white","blue","blue", "green")。什么是最好的解决方案？

【问题讨论】：

标签： r

【解决方案1】：

x <- c("white","white","blue","green","red","blue","red")
y <- c("red","white","blue","green")
x[order(match(x, y))]
# [1] "red"   "red"   "white" "white" "blue"  "blue"  "green"

【讨论】：

【解决方案2】：

使您的变量成为一个因子，其级别按适当的顺序排列，sort()：

 x1 <- c("white","white","blue","green","red","blue","red")
 ord <- c("red","white","blue","green")
 f1 <- factor(x1,levels=ord)
 sort(f1)
 ## [1] red   red   white white blue  blue  green
 ## Levels: red white blue green

如果您真的希望将结果作为字符向量，您可以使用x2 <- as.character(sort(f1)) ...

【讨论】：