| # File src/library/base/R/scale.R |
| # Part of the R package, https://www.R-project.org |
| # |
| # Copyright (C) 1995-2018 The R Core Team |
| # |
| # This program is free software; you can redistribute it and/or modify |
| # it under the terms of the GNU General Public License as published by |
| # the Free Software Foundation; either version 2 of the License, or |
| # (at your option) any later version. |
| # |
| # This program is distributed in the hope that it will be useful, |
| # but WITHOUT ANY WARRANTY; without even the implied warranty of |
| # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| # GNU General Public License for more details. |
| # |
| # A copy of the GNU General Public License is available at |
| # https://www.R-project.org/Licenses/ |
| |
| scale <- function(x, center = TRUE, scale = TRUE) UseMethod("scale") |
| |
| scale.default <- function(x, center = TRUE, scale = TRUE) |
| { |
| x <- as.matrix(x) |
| nc <- ncol(x) |
| if (is.logical(center)) { |
| if (center) { |
| center <- colMeans(x, na.rm=TRUE) |
| x <- sweep(x, 2L, center, check.margin=FALSE) |
| } |
| } |
| else { |
| if(!is.numeric(center)) center <- as.numeric(center) |
| if (length(center) == nc) |
| x <- sweep(x, 2L, center, check.margin=FALSE) |
| else |
| stop("length of 'center' must equal the number of columns of 'x'") |
| } |
| if (is.logical(scale)) { |
| if (scale) { |
| f <- function(v) { |
| v <- v[!is.na(v)] |
| sqrt(sum(v^2) / max(1, length(v) - 1L)) |
| } |
| scale <- apply(x, 2L, f) |
| x <- sweep(x, 2L, scale, "/", check.margin=FALSE) |
| } |
| } |
| else { |
| if(!is.numeric(scale)) scale <- as.numeric(scale) |
| if (length(scale) == nc) |
| x <- sweep(x, 2L, scale, "/", check.margin=FALSE) |
| else |
| stop("length of 'scale' must equal the number of columns of 'x'") |
| } |
| if(is.numeric(center)) attr(x, "scaled:center") <- center |
| if(is.numeric(scale )) attr(x, "scaled:scale" ) <- scale |
| x |
| } |