因數轉換錯誤

Question

我正在嘗試將數據幀中的三個字符變量轉換為因數，而這三個變量之一始終會出錯。 有問題的變量fund.category具有四個可能的值：“未定義”，“小”，“大型現有”和“大型新建”。 我的代碼如下-我首先使用XLConnect從excel工作表中讀取數據幀，然后刪除不必要的變量並將其重命名為我保留的變量：

a.projects <- readWorksheet(wb, sheet = "ProjectsDetail")
a.projects.2 <- a.projects[c("ProjectNumber", "BusinessType", "Fund.Category")]
a.projects.2 <- rename(a.projects.2,
                       c("ProjectNumber" = "project.number",
                         "BusinessType" = "business.type",
                         "Fund.Category" = "fund.catetgory"))
str(a.projects.2)
a.projects.2$project.number <- as.factor(a.projects.2$project.number)
a.projects.2$business.type <- as.factor(a.projects.2$business.type)   
a.projects.2$fund.category <- as.factor(a.projects.2$fund.category)  

這是a.projects.2的結構，它是在我嘗試進行因子轉換之前生成的：

'data.frame':   4291 obs. of  3 variables:
 $ project.number: chr  "APS-10-02825" "APS-10-02826" "APS-10-02876" "APS-10-03134" ...
 $ business.type : chr  "Office" "Office" "Process Industrial" "K-12 School" ...
 $ fund.catetgory: chr  "Undefined" "Undefined" "Large Existing" "Large New Construction" ...

這是來自控制台的錯誤：

a.projects.2$fund.category <- as.factor(a.projects.2$fund.category)

Error in `$<-.data.frame`(`*tmp*`, "fund.category", value = integer(0)) : 
replacement has 0 rows, data has 4291

對於其他兩個字符變量（project.number和business.type），相同的代碼未產生任何錯誤。 任何想法為什么這不起作用？

Answer 1

您在先前的聲明中拼寫了“ fund.category”：

a.projects.2 <- rename(a.projects.2,
                       c("ProjectNumber" = "project.number",
                         "BusinessType" = "business.type",
                         "Fund.Category" = "fund.catetgory"))

修正錯字，應該很開心:-)

---

要了解錯誤，

a.projects.2$fund.category返回NULL

as.factor(NULL)返回factor(0)

並且是在將factor(0)分配給a.projects.2$fund.category出現錯誤：

Error in `$<-.data.frame`(`*tmp*`, "fund.category", value = integer(0)) : 
replacement has 0 rows, data has 4291