R按索引字符串排序字符串

Question

我想按字符串索引对矩阵进行排序

例如

矩阵是
myMat =
      [,1]           [,2]
[1,] 苹果         1
[2,] 香蕉      3
[3,] 梨           4
[4,] 黑莓 5

索引字符串是
我的身份 =
[1,]香蕉
[2,]梨
[3,]苹果
[4,]黑莓

结果必须是
myResult=

      [,1]           [,2]
[1,] 香蕉      3
[2,] 梨           4
[3,] 苹果         1
[4,] 黑莓 5

我怎样才能这样排序？谢谢

Answer 1

使用data.table 包你可以很容易地做到这一点

myMat <- data.frame(fruit = c("apple", "banana", "pear", "blackberry"), num = c(1, 3, 4, 5))
myIdx <- c("banana", "pear", "apple", "blackberry")

require(data.table)
myMat <- data.table(myMat)
myMat
##         fruit num
## 1:      apple   1
## 2:     banana   3
## 3:       pear   4
## 4: blackberry   5

setkey(myMat, fruit)
myMat[J(myIdx)]

##         fruit num
## 1:     banana   3
## 2:       pear   4
## 3:      apple   1
## 4: blackberry   5