| matrix {base} | R Documentation |
matrix creates a matrix from the given set of values.
as.matrix attempts to turn its argument into a matrix.
is.matrix tests if its argument is a (strict) matrix.
matrix(data = NA, nrow = 1, ncol = 1, byrow = FALSE,
dimnames = NULL)
as.matrix(x, ...)
## S3 method for class 'data.frame':
as.matrix(x, rownames.force = NA, ...)
is.matrix(x)
data |
an optional data vector. |
nrow |
the desired number of rows. |
ncol |
the desired number of columns. |
byrow |
logical. If FALSE (the default) the matrix is
filled by columns, otherwise the matrix is filled by rows. |
dimnames |
A dimnames attribute for the matrix: a
list of length 2 giving the row and column names respectively. |
x |
an R object. |
... |
additional arguments to be passed to or from methods. |
rownames.force |
logical indicating if the resulting matrix
should have character (rather than NULL)
rownames. The default, NA, uses NULL
rownames if the data frame has ‘automatic’ row.names or for a
zero-row data frame. |
If either of nrow or ncol is not given, an attempt is
made to infer it from the length of data and the other
parameter.
If there are too few elements in data to fill the array,
then the elements in data are recycled. If data has
length zero, NA of an appropriate type is used for atomic
vectors (0 for raw vectors) and NULL for lists.
is.matrix returns TRUE if x is a matrix and has a
dim attribute of length 2) and FALSE otherwise.
Note that a data.frame is not a matrix by this
test. It is generic: you can write methods to handle
specific classes of objects, see InternalMethods.
as.matrix is a generic function. The method for data frames
will return a character matrix if there is any
non-(numeric/logical/complex) column, applying format to
non-character columns. Otherwise, the usual coercion hierarchy
(logical < integer < double < complex) will be used, e.g., all-logical
data frames will be coerced to a logical matrix, mixed logical-integer
will give a integer matrix, etc.
When coercing a vector, it produces a one-column matrix, and promotes the names (if any) of the vector to the rownames of the matrix.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
data.matrix, which attempts to convert to a numeric matrix.
is.matrix(as.matrix(1:10))
!is.matrix(warpbreaks)# data.frame, NOT matrix!
warpbreaks[1:10,]
as.matrix(warpbreaks[1:10,]) #using as.matrix.data.frame(.) method
# Example of setting row and column names
mdat <- matrix(c(1,2,3, 11,12,13), nrow = 2, ncol=3, byrow=TRUE,
dimnames = list(c("row1", "row2"), c("C.1", "C.2", "C.3")))
mdat