| # File src/library/stats/R/lag.R |
| # Part of the R package, https://www.R-project.org |
| # |
| # Copyright (C) 1995-2012 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/ |
| |
| lag <- function(x, ...) UseMethod("lag") |
| |
| lag.default <- function(x, k = 1, ...) |
| { |
| if(k != round(k)) { |
| k <- round(k) |
| warning("'k' is not an integer") |
| } |
| x <- hasTsp(x) |
| p <- tsp(x) |
| tsp(x) <- p - (k/p[3L]) * c(1, 1, 0) |
| x |
| } |