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 x . |
scale |
either a logical value or a numeric vector of length
equal to the number of columns of x . |
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 standard deviations, and if
scale
is FALSE
, no scaling is done.
The standard deviation 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 (whether or not centering was done).
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