重新編碼缺少字符字段中的數據

Question

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我有一個奇怪的情況，一個調查的答案都是字符，而不是數字。看來，R，真的不喜歡這個。假設我提出了一個問題：

Q. In what area do you work? 
East 
West 
Central 
North 
South 
None of the above 

但受訪者只來自東部，西部和中部。

dat <- rep(c("East", "West", "Central"),100) 

現在，爲了演示目的，重要的是我包括北，南，以上都不是，即使他們沒有。然而，考慮到這些因素是具有挑戰性的。

讓我們嘗試：

fac1 <- factor(dat, labels=c("East","West","Central","North","South","None of the above")) 

Error in factor(dat, labels = c("East", "West", "Central", "North", "South", : 
    invalid labels; length 6 should be 1 or 3 

基本上，我想要做的就是因素把這個數據與缺失值。因此，當我輸入類似摘要（fac1）的內容時，它顯示他們在該類別中有0個回覆。

必須有一個更簡單的方法來做到這一點！

Answer 1

幾乎在那裏。您需要使用levels參數：

fac1 <- factor(dat, levels=c("East","West","Central","North","South","None of the above")) 
str(fac1) 
Factor w/ 6 levels "East","West",..: 1 2 3 1 2 3 1 2 3 1 ... 

---

levels和labels之間的區別是這樣的：

• levels定義你的數據因子水平
• labels可以讓你重新命名因子水平一氣呵成。

例如：

fac2 <- factor(
    dat, 
    levels=c("East","West","Central","North","South","None of the above"), 
    labels=c("E", "W", "C", "N", "S", "Other") 
) 
str(fac2) 
Factor w/ 6 levels "E","W","C","N",..: 1 2 3 1 2 3 1 2 3 1 ... 

Answer 2

不是專家，但是這是任何幫助嗎？

fac1 <- factor(dat, levels = 
       c("East","West","Central","North","South","None of the above")) 
summary(fac1)