Vectors

Description

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 mode is most convenient). The attributes of x are removed.

is.vector returns TRUE if x is a vector (of mode logical, integer, real, complex, character or list if not specified) and FALSE otherwise.

Usage

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

Arguments

Details

is.vector returns FALSE if x has any attributes except names. (This is incompatible with S.) On the other hand, as.vector removes all attributes including names.

Note that factors are not vectors; is.vector returns FALSE and as.vector converts to character mode.

Value

For vector, a vector of the given length and mode. Logical vector elements are initialized to FALSE, numeric vector elements to 0 and character vector elements to "".

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

df <- data.frame(x=1:3, y=5:7)
## Not run: 
## Error:
  as.vector(data.frame(x=1:3, y=5:7), mode="numeric")
## End(Not run)

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")
is.vector(NULL,   mode="NULL")