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 2.1.0 Index]