numeric                 package:base                 R Documentation

Numeric Vectors

Description:

     `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.

Usage:

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

Arguments:

  length: desired length.

       x: object to be coerced or tested.

     ...: further arguments passed to or from other methods.

Note:

     R has no single precision data type.  All real numbers are stored
     in double precision format. While `as.numeric' is a generic
     function, user methods must be written for `as.double', which it
     calls

     `as.numeric' for factors yields the codes underlying the factor
     levels, not the numeric representation of the labels.

Examples:

     as.numeric(c("-.1"," 2.7 ","B")) # (-0.1, 2.7, NA)  +  warning
     as.numeric(factor(5:10))

