# Factors

Factors are a variable type used for categorial data.

Whenever a data frame is created with text strings, R treats it as a factor.

Want to learn more? I recommend working through: R for Data Science, R Cookbook, and R Graphics Cookbook.

# Create three variables of 50 observations length. turnout <- runif(50) state <- state.name outcome <- c("win", "loss")

# Create a dataframe of those two variables usa <- data.frame(state, turnout, outcome)

# Is "outcome" a factor? Yes. class(usa$outcome)

[1] "factor"

# View the levels (i.e. category names) of the factor levels(usa$outcome)

[1] "loss" "win"

# views the number of these levels (i.e. category IDs) of the factor nlevels(usa$outcome)

[1] 2

# change levels of a factor levels(usa$outcome) <- c("victory", "defeat")