如何在使用两个不同的变量时进行子集(以创建一个桶形图)

Question

但是，当我运行以下代码时，我试图使用两个不同的变量生成一个子集：

progressive.vote.demo <- subset(dbj, subset == progressive.vote & republican == 0)

它产生了以下错误消息：

子集== progressive.vote中的错误:比较(1)只能用于原子类型和列表类型

这样我就可以做一张桌子来运行一个酒吧：

democrats.table <- table(democrats$judge.birthyear == "before 1935",
democrats$judge.birthyear == "from 1935", dbj$progressive.vote)

barplot(democrats.table)

Answer 1

您是否试图传递一个变量，而不是字符串(比如"progressive.vote")？欢迎作出更多的澄清。

dbj=as.data.frame(cbind(subset=c(rep("progressive.vote",2),rep("conservative.vote",2)),republican=c(0,1,0,1)))
dbj
     subset              republican
[1,] "progressive.vote"  "0"       
[2,] "progressive.vote"  "1"       
[3,] "conservative.vote" "0"       
[4,] "conservative.vote" "1"    

subset(dbj, subset == "progressive.vote" & republican == 0)
        subset republican
1 progressive.vote          0