如何在R中使用带剪切功能的重复标签?

v<-c(3,2,9,3,4,10,-4) # example vector
c<-cut(v,breaks=c(-10,0,3,8,Inf),labels=c("blue","yellow","green","orange"))
c
[1] yellow yellow orange yellow green  orange blue  
Levels: blue yellow green orange

我的问题是,我现在想投影一系列数字来给重复使用颜色的“标签”上色,例如获得条纹效果:

c<-cut(v,breaks=c(-10,0,3,8,Inf),labels=c("blue","green","blue","green"))

但这给了我一个错误:

factor level [3] is duplicated

我预料到了