set.seed(12345)
a<- sample(2,nrow(wdbc),replace = TRUE,prob = c(0.8,0.2))
train<- wdbc[a==1,-1]
test<- wdbc[a==2,-1]
str(train$Diagnosis)

library(class)
?knn
knn.model<- knn(train,test,train$Diagnosis,k=6)


有老师知道吗，程序哪里写的不对吗，knn报错。