data.matrix {base} | R Documentation |

## Data Frame to Numeric Matrix

### Description

Return the matrix obtained by converting all the variables in a data
frame to numeric mode and then binding them together as the columns of
a matrix. Factors and ordered factors are replaced by their internal
codes.

### Usage

data.matrix(frame)

### Arguments

`frame` |
a data frame whose components are logical vectors,
factors or numeric vectors. |

### Details

Suppling a data frame with columns which are not numerical or logical
is an error. A warning is given if any non-factor column as a class,
as then information can be lost.

### References

Chambers, J. M. (1992)
*Data for models.*
Chapter 3 of *Statistical Models in S*
eds J. M. Chambers and T. J. Hastie, Wadsworth & Brooks/Cole.

### See Also

`as.matrix`

,
`data.frame`

,
`matrix`

.

### Examples

DF <- data.frame(a=1:3, b=letters[10:12],
c=seq(as.Date("2004-01-01"), by = "week", len = 3))
data.matrix(DF[1:2])
data.matrix(DF) # gives a warning and quotes dates as #days since 1970.

[Package

*base* version 2.2.1

Index]