使用`transform`函數對分類變量中的值進行排序

Question

我有一個像這樣的測試數據集：

table(spamday)  
FR MO SA SU TH TU WE  
30 96  9  9 45 60 51

結構：

str(spamday)  
'data.frame':   300 obs. of  1 variable:
$ SPAMreceived: Factor w/ 7 levels "FR","MO","SA",..: 2 5 5 5 6 2 6 2 2 6 ...  

我的目標是使用transform函數使分類變量成為有序因子，並使用levels指令強加的順序

所以我運行以下代碼：

spamday <- transform(spamday, SPAMreceived <- factor(SPAMreceived, levels = c("MO", "TU", "WE", "TH", "FR", "SA", "SU"), ordered = TRUE))

你猜怎么着？ 沒有任何反應......當使用table時仍然相同：

table(spamday)  
FR MO SA SU TH TU WE  
30 96  9  9 45 60 51

我很困惑......我做錯了什么？

Answer 1

這是一個有點硬，有時跟蹤時使用<-當不使用它，但是這是在你不想使用它的情況。 換句話說，只需將代碼更改為以下內容即可：

spamday <- transform(spamday, SPAMreceived = factor(SPAMreceived, 
    levels = c("MO", "TU", "WE", "TH", "FR", "SA", "SU"), ordered = TRUE)) 

這是一個小例子：

set.seed(1)
spamday <- data.frame(SPAMreceived = sample(c("FR", "MO", "SA", "SU", "TH", "TU", "WE"),
                                            50, replace = TRUE))
table(spamday$SPAMreceived)
# 
# FR MO SA SU TH TU WE 
#  5  7  7  6  9 10  6

temp <- transform(spamday, SPAMreceived = factor(SPAMreceived, 
    levels = c("MO", "TU", "WE", "TH", "FR", "SA", "SU"), ordered = TRUE))
table(temp$SPAMreceived)
# 
# MO TU WE TH FR SA SU 
#  7 10  6  9  5  7  6 

---

或者，您甚至不需要創建有序因子列。 只是在最后階段排序你的表:)

table(spamday$SPAMreceived)[c("MO", "TU", "WE", "TH", "FR", "SA", "SU")]
# 
# MO TU WE TH FR SA SU 
#  7 10  6  9  5  7  6