计算一个向量的值在另一个向量中的出现次数 [英] Count the occurrence of one vector's values in another vector

问题描述

我有两个向量

v1 <- c(164,38,20,19,163,22,21,4) 
v2 <- c(0,21,164,60,59,58,57,22,5,3,164,38,22,20,4,164,38,20,19,3,4,19,20,164,21,3,4,19,22,20,164,163,20,19,3)

我想计算向量 2 中向量 1 中数字的出现次数.我试图用循环来做，但由于表格的格式，它并没有完全奏效.

I would like to count the occurrence of the numbers in vector 1 in vector 2. I tried to do it with a loop but it didn't quite worked because of the format of the table.

a<-table(v2)
occurrence<-numeric()
for(i in v1){
   occurrence[i]<-a[names(a)==v1[i]]
}
occurSum<-sum(occurrence)

你知道一种最好不使用循环的方法吗?

Do you know a way to do this preferably without using a loop?

推荐答案

也许你正在寻找类似于 table 和 %in% 的组合:

Perhaps you are looking for something like a combination of table and %in%:

> table(v2[v2 %in% v1])

  4  19  20  21  22  38 163 164 
  3   4   5   2   3   2   1   5 

或者，在您尝试的基础上，您可以尝试:

Or, building on your attempt, you might try:

tv2 <- table(v2)
tv2[match(v1, names(tv2))]

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