如何在 R 中将分类变量转换为数值？

Question

我对 R 很陌生

我有以下数据集

age    sex    bmi children smoker    region   charges  sex_N
1  19 female 27.900        0    yes southwest 16884.924 female
2  18   male 33.770        1     no southeast  1725.552   male
3  28   male 33.000        3     no southeast  4449.462   male
4  33   male 22.705        0     no northwest 21984.471   male
5  32   male 28.880        0     no northwest  3866.855   male
6  31 female 25.740        0     no southeast  3756.622 female

我想根据其他列预测费用，但其他列是分类的如何将它们更改为数字变量？

我试过costs$sex_N <- as.factor(costs$sex)但是没有给我正确的列，正如你在上面看到的那样？

另外，如果列的唯一值大于 2 ，如何转换它们？请帮助！

Answer 1

这里有两个可能有用的基础 R 选项

> transform(
+   costs,
+   sex_N = as.integer(as.factor(sex_N))
+ )
  age    sex    bmi children smoker    region   charges sex_N
1  19 female 27.900        0    yes southwest 16884.924     1
2  18   male 33.770        1     no southeast  1725.552     2
3  28   male 33.000        3     no southeast  4449.462     2
4  33   male 22.705        0     no northwest 21984.471     2
5  32   male 28.880        0     no northwest  3866.855     2
6  31 female 25.740        0     no southeast  3756.622     1

或

> transform(
+   costs,
+   sex_N = match(sex_N, sex_N)
+ )
  age    sex    bmi children smoker    region   charges sex_N
1  19 female 27.900        0    yes southwest 16884.924     1
2  18   male 33.770        1     no southeast  1725.552     2
3  28   male 33.000        3     no southeast  4449.462     2
4  33   male 22.705        0     no northwest 21984.471     2
5  32   male 28.880        0     no northwest  3866.855     2
6  31 female 25.740        0     no southeast  3756.622     1

如何在 R 中将分类变量转换为数值？

How to convert categorical variable to numerical in R?

r

linear-regression