is.dummy {str2str}

Test for a Dummy Variable

Description

is.dummy returns whether a numeric vector is a dummy variable, meaning all elements one of two observed values (or missing values). Depending on the argument any.values, the two observed values are required to be 0 and 1 or any values.

Usage

is.dummy(x, any.values = FALSE)

Arguments

x

atomic vector.

any.values

logical vector of length 1 specifying whether the two observed values need to be 0 or 1 (FALSE) or can be any values (TRUE).

Value

TRUE if 'x' is a dummy variable; FALSE otherwise.

Examples

# any.values = FALSE (default)
is.dummy(mtcars$"am") # TRUE
is.dummy(c(mtcars$"am", NA, NaN)) # works with missing values
is.dummy(c(as.integer(mtcars$"am"), NA, NaN)) # works with typeof integer
x <- ifelse(mtcars$"am" == 1, yes = 2, no = 1)
is.dummy(x) # FALSE

# any.values = TRUE
is.dummy(x, any.values = TRUE) # TRUE
is.dummy(c(x, NA), any.values = TRUE) # work with missing values
is.dummy(c(as.character(x), NA), any.values = TRUE) # work with typeof character
is.dummy(mtcars$"gear") # FALSE for nominal variables with more than 2 levels