# Single variable
dnum(iris2$Sepal.Length)
dnum(iris2["Sepal.Length"])
dnum(iris2[, "Sepal.Length"])
# Multiple variables
dnum(iris2[, c("Sepal.Length", "Sepal.Width")])
# Will not save you from yourself (will create numeric data for factors):
dnum(iris2$Species)
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