R 将因子名称视为一个级别

Question

我从 Excel 文件中获取数据（两个变量，一个是分类变量，另一个是数值变量），然后将它们的类型相应地更改为因子和数值：

setwd("D:/Desktop/")
db_nouns = read.table ("Final_Database.txt")
db_nouns = db_nouns [2:507,]
colnames (db_nouns) = c ("category", "space")
db_nouns$category = as.factor (db_nouns$category)
db_nouns$space = as.numeric(as.character(db_nouns$space))

现在我想安排因子水平（对于类别），以便它们以特定顺序（稍后）出现在图上：

levels (db_nouns$category) = c( "Ground", "Building", "Tool_precise_grip", "Tool_power_grip", "Food", "Clothes", "Animal", "Object", "Transport", "Action", "Body_Part", "Sense_Phys", "Sound", "Sense_Emotion", "Intelligence", "Space")

但是，当我这样做时，我得到一个错误：

*Error in `levels<-.factor`(`*tmp*`, value = c("Ground", "Building", "Tool_precise_grip",  : 
  number of levels differs*

如果我检查 db_nouns$category 中的级别，我会得到一个额外的级别，称为“类别”，即 R 将因子的名称视为级别之一（参见下面的第 5 行）。我该如何解决这个问题？

> levels (db_nouns$category)
 [1] "Action"            "Animal"            "Body_Part"         "Building"         
 [5] "Category"          "Clothes"           "Food"              "Ground"           
 [9] "Intelligence"      "Object"            "Sense_Emotion"     "Sense_Phys"       
[13] "Sound"             "Space"             "Tool_power_grip"   "Tool_precise_grip"
[17] "Transport" 

Answer 1

读取数据时使用stringsAsFactors=T和header = T：

db_nouns <- read.table("Final_Database.txt", stringsAsFactors = T, header = T)

colnames(db_nouns) <- c ("category", "space")

new_order <- c( "Ground", "Building", "Tool_precise_grip", "Tool_power_grip", "Food", "Clothes", "Animal", "Object", "Transport", "Action", "Body_Part", "Sense_Phys", "Sound", "Sense_Emotion", "Intelligence", "Space")

db_nouns$category <- factor(db_nouns$category, levels = new_order)