scale {base} | R Documentation |
scale
is generic function whose default method centers and/or
scales the columns of a numeric matrix.
scale(x, center = TRUE, scale = TRUE)
x |
a numeric matrix(like object). |
center |
either a logical value or a numeric vector of length
equal to the number of columns of |
scale |
either a logical value or a numeric vector of length
equal to the number of columns of |
The value of center
determines how column centering is
performed.
If center
is a numeric vector with length equal to the number
of columns of x
, then each column of x
has the
corresponding value from center
subtracted from it.
If center
is TRUE
then centering is done by subtracting
the column means (omitting NA
s) of x
from their
corresponding columns, and if center
is FALSE
,
no centering is done.
The value of scale
determines how column scaling is performed
(after centering).
If scale
is a numeric vector with length equal to the number of
columns of x
, then each column of x
is divided by the
corresponding value from scale
.
If scale
is TRUE
then scaling is done by dividing the
(centered) columns of x
by their root-mean-square, and if
scale
is FALSE
, no scaling is done.
The root-mean-square for a column is obtained by computing the square-root of the sum-of-squares of the non-missing values in the column divided by the number of non-missing values minus one.
For scale.default
, the centered, scaled matrix. The numeric
centering and scalings used (if any) are returned as attributes
"scaled:center"
and "scaled:scale"
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
sweep
which allows centering (and scaling) with
arbitrary statistics.
For working with the scale of a plot, see par
.
require(stats)
x <- matrix(1:10, ncol=2)
(centered.x <- scale(x, scale=FALSE))
cov(centered.scaled.x <- scale(x))# all 1