r R中的移位向量

Posted 2021-05-23

# R Function to Shift Vectors
# http://clarkrichards.org/r/timeseries/2016/02/09/a-function-to-shift-vectors/
#

shift <- function(x, lag) {
    n <- length(x)
    xnew <- rep(NA, n)
    if (lag < 0) {
        xnew[1:(n-abs(lag))] <- x[(abs(lag)+1):n]
    } else if (lag > 0) {
        xnew[(lag+1):n] <- x[1:(n-lag)]
    } else {
        xnew <- x
    }
    return(xnew)
}