numeric {base} | R Documentation |

## Numeric Vectors

### Description

Creates or tests for objects of type `"numeric"`

.

### 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. |

### Details

`as.numeric`

is a generic function, but methods must be
written for `as.double`

, which it calls.

`is.numeric`

is generic: you can write methods to handle
specific classes of objects, see InternalMethods.

### Value

`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 `"double"`

(even if it is already `"integer"`

).
`as.numeric`

for factors yields the codes underlying the factor
levels, not the numeric representation of the labels, see also
`factor`

.

The default method for `is.numeric`

returns `TRUE`

if its argument is of mode `"numeric"`

(type `"double"`

or type `"integer"`

) and not a
factor, and `FALSE`

otherwise. That is,
`is.integer(x) || is.double(x)`

, or
`(mode(x) == "numeric") && !is.factor(x)`

.

### Note

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

`numeric`

and `as.numeric`

are the identical to `double`

and
`as.double`

(unless someone defines S4 methods on one of them).

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
*The New S Language*.
Wadsworth & Brooks/Cole.

### See Also

`double`

, `integer`

, `storage.mode`

.

### Examples

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

[Package

*base* version 2.5.0

Index]