r - 计算 R 中唯一值的交叉表

Question

我的数据由 3 列组成: - 部分 - 类别 - 产品编号

如何创建一个交叉表(“分割”作为列，“类别”作为行)来计算“产品编号”的唯一值强>”(下面的例子)？

      SEG1  SEG2  SEG3
CAT1   X
CAT2
CAT3

X - CAT1 和 SEG1 中唯一值的数量

示例数据

CAT<-c("CAT1","CAT3","CAT3","CAT1","CAT2","CAT3","CAT3","CAT3","CAT3","CAT2") 
SEG<-c("SEG1","SEG3","SEG3","SEG2","SEG2","SEG2","SEG3","SEG3","SEG2","SEG2")   
PRODUCT<-c("a","a","a","a","d","e","b","c","a","a")
data<-cbind(CAT,SEG,PRODUCT)

提前非常感谢!此致，巴特克

Answer 1

您可以简单地计算数据的交叉表，但无需重复行，以确保只计算唯一的产品编号:

nodup <- which(!duplicated(data))
table(data[nodup, "CAT"],data[nodup, "SEG"])

       SEG1 SEG2 SEG3
  CAT1    1    1    0
  CAT2    0    2    0
  CAT3    0    2    3