| rep {base} | R Documentation |
rep replicates the values in x. It is a generic
function, and the (internal) default method is described here.
rep.int is a faster simplified version for the most common case.
rep(x, ...) rep.int(x, times)
x |
a vector (of any mode including a list) or a pairlist or a
factor or (except for rep.int) a POSIXct or
POSIXlt or date object. |
... |
further arguments to be passed to or from other methods.
For the internal default method these can include:
|
times |
see .... |
The default behaviour is as if the call was rep(x, times=1,
length.out=NA, each=1). Normally just one of the additional
arguments is specified, but if code{each} is specified with either
of the other two, its replication is performed first, and then that
implied by times or length.out.
If times consists of a single integer, the result consists of
the whole input repeated this many times. If times is a
vector of the same length as x (after replication by
each), the result consists of x[1] repeated
times[1] times, x[2] repeated times[2] times and
so on.
length.out may be given in place of times,
in which case x is repeated as many times as is
necessary to create a vector of this length. If both are given,
length.out takes priority and times is ignored.
Non-integer values of times will be truncated towards zero.
If times is a computed quantity it is prudent to add a small fuzz.
If x has length zero and length.out is supplied and is
positive, the values are filled in using the extraction rules, that is
by an NA of the appropriate class for an atomic vector
(0 for raw vectors) and NULL for a list.
An object of the same type as x (except that rep will
coerce pairlists to vector lists).
rep.int returns no attributes.
The default method of rep gives the result names (which will
almost always contain duplicates) if x had names, but retains
no other attributes except for factors.
Function rep.int is a simple case handled by internal code, and
provided as a separate function purely for S compatibility.
As from R 2.4.0, function rep is a primitive, but (partial)
matching of argument names is performed as for normal functions.
You can no longer pass a missing argument to. e.g. length.out.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
rep(1:4, 2) rep(1:4, each = 2) # not the same. rep(1:4, c(2,2,2,2)) # same as second. rep(1:4, c(2,1,2,1)) rep(1:4, each = 2, len = 4) # first 4 only. rep(1:4, each = 2, len = 10) # 8 integers plus two recycled 1's. rep(1:4, each = 2, times = 3) # length 24, 3 complete replications rep(1, 40*(1-.8)) # length 7 on most platforms rep(1, 40*(1-.8)+1e-7) # better ## replicate a list fred <- list(happy = 1:10, name = "squash") rep(fred, 5) # date-time objects x <- .leap.seconds[1:3] rep(x, 2) rep(as.POSIXlt(x), rep(2, 3)) ## named factor x <- factor(LETTERS[1:4]); names(x) <- letters[1:4] x rep(x, 2) rep(x, each=2) rep.int(x, 2) # no names