matrix

R Base 3.6.2

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.

Syntax

matrix(data = NA, nrow = 1, ncol = 1, byrow = FALSE,
       dimnames = NULL)<p></p><p>as.matrix(x, &#8230;)
# S3 method for data.frame
as.matrix(x, rownames.force = NA, &#8230;)</p><p>is.matrix(x)</p>

Arguments

Parameter	Description
`data`	an optional data vector (including a list or expression vector). Non-atomic classed R objects are coerced by as.vector and all attributes discarded.
`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: NULL or a list of length 2 giving the row and column names respectively. An empty list is treated as NULL, and a list of length one as row names. The list can be named, and the list names will be used as names for the dimensions.
`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.

Details

If one of nrow or ncol is not given, an attempt is made to infer it from the length of data and the other parameter. If neither is given, a one-column matrix is returned. If there are too few elements in data to fill the matrix, 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 vector and has a "dim" attribute of length 2 and FALSE otherwise. Note that a data.frame is not a matrix by this test. The function 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 only atomic columns and any non-(numeric/logical/co

Examples

Example

# NOT RUN {
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
# }

matrix

Syntax

Arguments

Details

Examples

See Also