R: Numeric Vectors

Numeric Vectors

numeric(length = 0)
as.numeric(x)
is.numeric(x)

numeric creates a real vector of the specified length. The elements of the vector are all equal to 0.

as.numeric attempts to coerce its argument to numeric type (either integer or real).

is.numeric returns TRUE if its argument is of type real or type integer and FALSE otherwise.

R has no single precision data type. All real numbers are stored in double precision format.

as.numeric for factors yields the codes underlying the factor levels.

as.numeric(c("2","B"))
as.numeric(factor(5:10))