| cbind {base} | R Documentation |
Take a sequence of vector, matrix or data frames arguments and combine by columns or rows, respectively. There may be methods for other R classes.
cbind(..., deparse.level = 1)
rbind(..., deparse.level = 1)
... |
vectors or matrices. These can be given as named arguments. |
deparse.level |
integer controlling the construction of labels;
currently, |
The functions cbind and rbind are generic, with methods
for data frames. The data frame method will be used if an argument is
a data frame and the rest are vectors or matrices. There can be other
methods; in particular, there is one for time series objects.
The data frame method takes the classes of the columns from the first data frame. Factors are have their levels expanded as necessary (in the order of the levels of the levelsets of the factors encountered) and the result is an ordered factor if and only if all the components were ordered factors. (The last point differs from S-PLUS.)
If there are several matrix arguments, they must all have the same
number of columns (or rows) and this will be the number of columns (or
rows) of the result. If all the arguments are vectors, the number of
columns (rows) in the result is equal to the length of the longest
vector. Values in shorter arguments are recycled to achieve this
length (with a warning if they are recycled only
fractionally).
When the arguments consist of a mix of matrices and vectors the number of columns (rows) of the result is determined by the number of columns (rows) of the matrix arguments. Any vectors have their values recycled or subsetted to achieve this length.
For cbind (rbind), vectors of zero length are ignored
unless the result would have zero rows (columns), for S compatibility.
(Zero-extent matrices do not occur in S and are not ignored in R.)
A matrix or data frame combining the ... arguments
column-wise or row-wise.
For cbind (rbind) the column (row) names are taken from
the names of the arguments, or where those are not supplied by
deparsing the expressions given (if that gives a sensible name).
The names will depend on whether data frames are included:
see the examples.
The method dispatching is not done via
UseMethod(), but by C-internal dispatching.
Therefore, there is no need for, e.g., rbind.default.
The dispatch algorithm is described in the source file (‘.../src/main/bind.c’) as
For each argument we get the list of possible class memberships from the class attribute.
We inspect each class in turn to see if there is an an applicable method.
If we find an applicable method we make sure that it is identical to any method determined for prior arguments. If it is identical, we proceed, otherwise we immediately drop through to the default code.
If you want to combine other objects with data frames, it may be necessary to coerce them to data frames first.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth \& Brooks/Cole.
c to combine vectors (and lists) as vectors,
data.frame to combine vectors and matrices as a data
frame.
cbind(1, 1:7) # the `1' (= shorter vector) is recycled
cbind(1:7, diag(3))# vector is subset -> warning
cbind(0, rbind(1, 1:3))
cbind(I=0, X=rbind(a=1, b=1:3)) # use some names
xx <- data.frame(I=rep(0,2))
cbind(xx, X=rbind(a=1, b=1:3)) # named differently
cbind(0, matrix(1, nrow=0, ncol=4))#> Warning (making sense)
dim(cbind(0, matrix(1, nrow=2, ncol=0)))#-> 2 x 1