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 forvector)"any". - 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 modes "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
modes: 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
modecan 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 modem, 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)
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")
Community examples
[Example file for LinkedIn Learning: R for Data Science: Lunchbreak Lessons](https://linkedin-learning.pxf.io/rwkly_vector) ```r # vectors are the simplest data storage in R # They are like standard variables I.am.a.vector <- 1 # except they are closer to arrays I.am.a.vector <- c(1,2,3) I.am.a.vector <- c("twas","brillig","and","the","slithey","toves") another.vector <- c(1,"twas") #concatenate different types into a vector results in character # number of members vs number of characters length(I.am.a.vector) == 6 # length is number of members, not length of string sum(nchar(I.am.a.vector)) == 29 # length of complete "string" # Vectors are not strings. I.am.also.a.vector <- c("did","gyre","and","gimble","in","the","wabes") paste(I.am.a.vector,I.am.also.a.vector) # maybe not what you expected c(I.am.a.vector,I.am.also.a.vector) # end for end combination. # indexing into a vector I.am.a.vector[3] # first member is at position 1 I.am.a.vector[0] # nope I.am.a.vector[-3] # select all but element three I.am.a.vector[1:3] # select elements 1, 2 and 3 # need something like a python dictionary? names(I.am.a.vector) <- c("first","second","third","fourth","fifth","sixth") I.am.a.vector["second"] ```