Check Whether a Vector Is Dichotomous

Determines whether a vector contains at most two distinct values.

Usage

isDichotomous(x, strict = FALSE, na.rm = FALSE)

Arguments

x

a vector.

strict

logical. If TRUE, exactly two distinct values must be present. If FALSE (default), at most two distinct values are allowed.

na.rm

logical. If TRUE, missing values are removed before evaluation. If FALSE (default), the presence of NA results in NA (indeterminate status).

Value

TRUE, FALSE, or NA if the status cannot be determined because of missing values (see na.rm).

See also

Other data.predicate: flags(), isEuclid(), isLowCardinality(), isNumeric(), isWholeLike(), isZero(), nUnique()

Examples

isDichotomous(c(0, 1, 1))
#> [1] TRUE
isDichotomous(c(1, 1, 1))
#> [1] TRUE
isDichotomous(c(1, 1, 1), strict = TRUE)
#> [1] FALSE
isDichotomous(c(0, 1, NA))               # NA
#> [1] NA
isDichotomous(c(0, 1, NA), na.rm = TRUE)
#> [1] TRUE
isDichotomous(c("A", "A", "B"))
#> [1] TRUE
isDichotomous(c("A", "A", "B", "C"))
#> [1] FALSE
isDichotomous(factor(c("A", "A", "B", "C")))
#> [1] FALSE