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.
Noninteger 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)+1e7) # better ## replicate a list fred < list(happy = 1:10, name = "squash") rep(fred, 5) # datetime 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