返回最高級別因子

Question

我正在嘗試使用有序的分類變量。看起來最大最小函數應該與訂購的類別一起工作，但它不適用。

var<-factor(c("1","6","4","3","5","2"),levels=c("1","6","4","3","5","2")) 
max(levels(var)) 

我想代碼返回最後一個因子級別（2），但它返回第二個（6）。我究竟做錯了什麼？在此先感謝您的幫助

Answer 1

只需在factor函數中指定ordered參數，然後它將工作。請參閱以下內容：

#set the ordered argument to TRUE, so that R understands the order of the levels 
#and i.e. which one is min and which is max 
var<-factor(c("1","6","4","3","5","2"),levels=c("1","6","4","3","5","2"), ordered=TRUE) 

#and then 
> max(var) 
[1] 2 
Levels: 1 < 6 < 4 < 3 < 5 < 2