R {arules} によるアソシエーション分析の結果をどうやったら見やすく表示できるか試行錯誤中

library(arules)library(cowplot)
data("Adult")

rules <- apriori(Adult, 
                 parameter =list(supp =0.5,conf =0.9,target ="rules",maxlen=2))
rules_lhs <-as(lhs(rules),"list")#条件部
rules_rhs <-as(rhs(rules),"list")#結論部
rules_lhs <- sapply(rules_lhs,function(x)ifelse(length(x)==0,"",x))
lhs_len <-sapply(rules_lhs,length)
item_rhs <- unlist(rules_lhs)
rules_df <-as(rules,"data.frame")
rules_df2 <-data.frame(lhs=unlist(rules_lhs),
                      rhs=rep(unlist(rules_rhs),lhs_len),
                      support=rep(rules_df$support,lhs_len))
ggplot(rules_df2,aes(x = rhs, y = lhs))+
  geom_tile(aes(fill=support))