R 将几个虚拟变量列合并为 1 [英] R Merge Several Dummy Variable Columns into 1

问题描述

我正在尝试合并汽车数据框(插入符号包)中的几列.敞篷车、轿跑车、掀背车、轿车、旅行车"列有虚拟变量，我想创建 1 个名为 type 的列，列名取决于车辆的类型.

I am trying to merge several columns in the cars data frame (caret package). The columns "convertible, coupe, hatchback, sedan, wagon" have dummy variables and I would like to create 1 column named type with the column names depending on the type of vehicle.

library(caret)
data(cars)
head(cars)
colnames(cars)

以下是汽车数据框的列名:

Below are the column names of the cars data frame:

 [1] "Price"       "Mileage"     "Cylinder"    "Doors"       "Cruise"        
 [6] "Sound"       "Leather"     "Buick"       "Cadillac"    "Chevy"     
[11] "Pontiac"     "Saab"        "Saturn"      "convertible" "coupe"   
[16] "hatchback"   "sedan"       "wagon" 

如何将最后 5 个虚拟变量列与相应的车辆类型合并/合并为 1 个?

How can I merge/consolidate the last 5 dummy variable columns into 1 with the corresponding vehicle type?

任何见解或帮助将不胜感激！

Any insight or assistance would be greatly appreciated!

推荐答案

使用 max.col 的矢量化解决方案:

A vectorized solution with max.col:

cars$type <- names(cars[14:18])[max.col(cars[14:18])]

作为替代解决方案，您可以使用 match:

As an alternative solution, you could use match:

cars$type <- names(cars[14:18])[apply(cars[14:18], 1, match, x = 1)] 

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