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.
It is generic: you can write methods to handle
specific classes of objects, see InternalMethods.

matrix(data = NA, nrow = 1, ncol = 1, byrow = FALSE, dimnames = NULL) as.matrix(x) 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. |

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 (i.e., it
is *not* a `data.frame`

and has a `dim`

attribute of length 2) and `FALSE`

otherwise.

`as.matrix`

is a generic function. The method for data frames
will convert any non-numeric/complex column into a character
vector using `format`

and so return a character matrix,
except that all-logical data frames will be coerced to a logical 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

[Package *base* version 2.1.0 Index]