大家看一下，不知道错在哪里？

b<-subset(m,m[,1]==1&m[,2]==m[,4])$item.x

b

with(subset(recommendation[user==1,]),which(item==101))

with(subset(recommendation[user==1,]),which(item==102))

with(subset(recommendation[user==1,]),which(b%in%item))

> b<-subset(m,m[,1]==1&m[,2]==m[,4])$item.x
> b
[1] 101 102

> with(subset(recommendation[user==1,]),which(item==101))

[1] 1
> with(subset(recommendation[user==1,]),which(item==102))
[1] 3
> with(subset(recommendation[user==1,]),which(b%in%item))
[1] 1 2

应该输出1和3呀怎么是2[cry]