将分类列转换为多个二进制列

Question

我想将此列转换为每个品种的二进制列（1 条狗是品种，0 条狗不是那个品种）

Answer 1

一种方法是使用 unique 和 for-loop

Breed = c(
  "Sheetland Sheepdog Mix",
  "Pit Bull Mix",
  "Lhasa Aposo/Miniature",
  "Cairn Terrier/Chihuahua Mix",
  "American Pitbull",
  "Cairn Terrier",
  "Pit Bull Mix"
)
df=data.frame(Breed)

for (i in unique(df$breed)){
  df[,paste0(i)]=ifelse(df$Breed==i,1,0)
}

Answer 2

使用 model.matrix() 将分类变量转换为二进制变量。

Breed = c(
  "Sheetland Sheepdog Mix",
  "Pit Bull Mix",
  "Lhasa Aposo/Miniature",
  "Cairn Terrier/Chihuahua Mix",
  "American Pitbull",
  "Cairn Terrier",
  "Pit Bull Mix"
)
df=data.frame(Breed)

dfcat = data.frame(model.matrix(~ df$Breed-1, data=df))
names(dfcat) = levels(df$Breed)

因此 dfcat 包含您的二进制变量：

dfcat
#American Pitbull Cairn Terrier Cairn Terrier/Chihuahua Mix Lhasa Aposo/Miniature Pit Bull Mix Sheetland Sheepdog Mix
#              0             0                           0                     0            0                      1
#              0             0                           0                     0            1                      0
#              0             0                           0                     1            0                      0
#              0             0                           1                     0            0                      0
#              1             0                           0                     0            0                      0
#              0             1                           0                     0            0                      0
#              0             0                           0                     0            1                      0

将分类列转换为多个二进制列

Convert categorical column to multiple binary columns

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