# vector

##### Vectors

`vector`

produces a vector of the given length and mode.

`as.vector`

, a generic, attempts to coerce its argument into a
vector of mode `mode`

(the default is to coerce to whichever
vector mode is most convenient): if the result is atomic all
attributes are removed.

`is.vector`

returns `TRUE`

if `x`

is a vector of the
specified mode having no attributes *other than names*. It returns
`FALSE`

otherwise.

- Keywords
- classes

##### Usage

```
vector(mode = "logical", length = 0)
as.vector(x, mode = "any")
is.vector(x, mode = "any")
```

##### Arguments

- mode
character string naming an atomic mode or

`"list"`

or`"expression"`

or (except for`vector`

)`"any"`

. Currently,`is.vector()`

allows any type (see`typeof`

) for`mode`

, and when mode is not`"any"`

,`is.vector(x, mode)`

is almost the same as`typeof(x) == mode`

.- length
a non-negative integer specifying the desired length. For a long vector, i.e.,

`length > .Machine$integer.max`

, it has to be of type`"double"`

. Supplying an argument of length other than one is an error.- x
an R object.

##### Details

The atomic modes are `"logical"`

, `"integer"`

,
`"numeric"`

(synonym `"double"`

), `"complex"`

,
`"character"`

and `"raw"`

.

If `mode = "any"`

, `is.vector`

may return `TRUE`

for
the atomic modes, `list`

and `expression`

.
For any `mode`

, it will return `FALSE`

if `x`

has any
attributes except names. (This is incompatible with S.) On the other
hand, `as.vector`

removes *all* attributes including names
for results of atomic mode (but not those of mode `"list"`

nor
`"expression"`

).

Note that factors are *not* vectors; `is.vector`

returns
`FALSE`

and `as.vector`

converts a factor to a character
vector for `mode = "any"`

.

##### Value

For `vector`

, a vector of the given length and mode. Logical
vector elements are initialized to `FALSE`

, numeric vector
elements to `0`

, character vector elements to `""`

, raw
vector elements to `nul`

bytes and list/expression elements to
`NULL`

.

For `as.vector`

, a vector (atomic or of type list or expression).
All attributes are removed from the result if it is of an atomic mode,
but not in general for a list result. The default method handles 24
input types and 12 values of `type`

: the details of most
coercions are undocumented and subject to change.

For `is.vector`

, `TRUE`

or `FALSE`

.
`is.vector(x, mode = "numeric")`

can be true for vectors of types
`"integer"`

or `"double"`

whereas ```
is.vector(x, mode =
"double")
```

can only be true for those of type `"double"`

.

##### Note

`as.vector`

and `is.vector`

are quite distinct from the
meaning of the formal class `"vector"`

in the methods
package, and hence `as(x, "vector")`

and
`is(x, "vector")`

.

Note that `as.vector(x)`

is not necessarily a null operation if
`is.vector(x)`

is true: any names will be removed from an atomic
vector.

Non-vector `mode`

s `"symbol"`

(synonym `"name"`

) and
`"pairlist"`

are accepted but have long been undocumented: they
are used to implement `as.name`

and
`as.pairlist`

, and those functions should preferably be
used directly. None of the description here applies to those
`mode`

s: see the help for the preferred forms.

##### Methods for `as.vector()`

Writers of methods for `as.vector`

need to take care to
follow the conventions of the default method. In particular

Argument

`mode`

can be`"any"`

, any of the atomic modes,`"list"`

,`"expression"`

,`"symbol"`

,`"pairlist"`

or one of the aliases`"double"`

and`"name"`

.The return value should be of the appropriate mode. For

`mode = "any"`

this means an atomic vector or list.Attributes should be treated appropriately: in particular when the result is an atomic vector there should be no attributes, not even names.

`is.vector(as.vector(x, m), m)`

should be true for any mode`m`

, including the default`"any"`

.

##### References

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

##### See Also

`c`

, `is.numeric`

, `is.list`

, etc.

##### Examples

`library(base)`

```
# NOT RUN {
df <- data.frame(x = 1:3, y = 5:7)
## Error:
try(as.vector(data.frame(x = 1:3, y = 5:7), mode = "numeric"))
x <- c(a = 1, b = 2)
is.vector(x)
as.vector(x)
all.equal(x, as.vector(x)) ## FALSE
###-- All the following are TRUE:
is.list(df)
! is.vector(df)
! is.vector(df, mode = "list")
is.vector(list(), mode = "list")
# }
```

*Documentation reproduced from package base, version 3.4.3, License: Part of R 3.4.3*