factor2var function

Create Dummy Variables

Create dummy variables from a categorical variable.

factor2var(
  x_value,
  x_contrasts = "contr.treatment",
  prefix = "",
  add_rownames = TRUE
)

Arguments

• x_value: The vector of categorical variable.
• x_contrasts: The contrast to be used. Default is "constr.treatment".
• prefix: The prefix to be added to the variables to be created. Default is "".
• add_rownames: Whether row names will be added to the output. Default is TRUE.

Returns

It always returns a matrix with the number of rows equal to the length of the vector (x_value). If the categorical has only two categories and so only one dummy variable is needed, the output is still a one-column "matrix" in R.

Details

Its main use is for creating dummy variables (indicator variables) from a categorical variable, to be used in lavaan::sem().

Optionally, the other contrasts can be used through the argument x_contrasts.

Examples

dat <- data_mod_cat
dat <- data.frame(dat,
                  factor2var(dat$w, prefix = "gp", add_rownames = FALSE))
head(dat[, c("w", "gpgroup2", "gpgroup3")], 15)