R: Recipes for Analysis, Visualization and Machine Learning

Creating dummies for categorical variables

In situations where we have categorical variables (factors) but need to use them in analytical methods that require numbers (for example, K nearest neighbors (KNN), Linear Regression), we need to create dummy variables.

Getting ready

Read the data-conversion.csv file and store it in the working directory of your R environment. Install the dummies package. Then read the data:

> install.packages("dummies")
> library(dummies)
> students <- read.csv("data-conversion.csv")

How to do it...

Create dummies for all factors in the data frame:

> students.new <- dummy.data.frame(students, sep = ".")
> names(students.new)

[1] "Age"      "State.NJ" "State.NY" "State.TX" "State.VA"
[6] "Gender.F" "Gender.M" "Height"   "Income"