在R中是否有一种不那么丑的方法来实现滑动窗口

我想从向量x得到一个滑动窗口em，大概是这样的

x <- 1:10
em <- embed(x,dimension = 3) [,3:1]
em <- rbind(matrix(NA,nrow = length(x)-nrow(em),ncol = ncol(em)),em)

..

em
      [,1] [,2] [,3]
 [1,]   NA   NA   NA
 [2,]   NA   NA   NA
 [3,]    1    2    3
 [4,]    2    3    4
 [5,]    3    4    5
 [6,]    4    5    6
 [7,]    5    6    7
 [8,]    6    7    8
 [9,]    7    8    9
[10,]    8    9   10
> x
 [1]  1  2  3  4  5  6  7  8  9 10

但我绝对不喜欢这个代码，它很繁琐，也很难理解. 你能给我推荐一些你觉得更简洁的 Select 吗？

= 做了一个小小的比较

   n <- 5
x <- 1:200

fu1 <- function(x, n){
  m <- embed(x,dimension = n) [,n:1]
  rbind(matrix(NA,nrow = length(x)-nrow(m),ncol = ncol(m)),m)
  m
}

fu2 <- function(x, n){
  m <- matrix(NA, nrow = length(x), ncol = n)
  m[n:length(x),] <- t(sapply(1:(length(x)-(n-1)), function(i) x[i:(i+(n-1))]))
  m
}

fu3 <- function(x, n){
  m <- matrix(NA, nrow = length(x), ncol = n)
  for (i in n:length(x))  m[i,] <- x[(i-(n-1)):(i)]
  m
}

fu4 <- function(x, n){
  m <- zoo::rollapply(data = x, width = n, FUN = as.list)
  m <- rbind(matrix(NA,nrow = length(x)-nrow(m),ncol = ncol(m)),m)
  m
}

fu5 <- function(x, n){
  zoo::rollapplyr(x, n, c, fill = NA)
}

fu6 <- function(x, n){
k <- seq_along(x)
idx <- c(outer(head(k, 1 - n), head(k - 1, n), `+`))
m <- matrix(x[idx], ncol = n)
rbind(matrix(NA,nrow = length(x)-nrow(m),ncol = ncol(m)),m)
}

fu7 <- function(x, n){
m <- t(sapply(head(seq_along(x), 1 - n), \(k) x[k:(k + (n-1))]))
rbind(matrix(NA,nrow = length(x)-nrow(m),ncol = ncol(m)),m)
}

.....

microbenchmark::microbenchmark( fu1(x,n), 
                                fu2(x,n), 
                                fu3(x,n), 
                                fu4(x,n),
                                fu5(x,n),
                                fu6(x,n),
                                fu7(x,n))
Unit: microseconds
      expr       min         lq       mean     median         uq       max neval
 fu1(x, n)    90.657   120.5910   140.4726   133.4195   142.5420   511.441   100
 fu2(x, n)   898.586  1011.4790  1295.2010  1071.6320  1174.2625 11882.315   100
 fu3(x, n)   322.716   371.4650   851.5983   387.4300   417.3635 23120.339   100
 fu4(x, n)  8308.497  9917.2290 11594.9786 10481.1260 11391.4000 37111.138   100
 fu5(x, n) 23263.451 26653.6745 29845.5357 27709.9120 30243.4565 80859.609   100
 fu6(x, n)   192.147   238.0455   271.7939   270.2610   291.3560   522.844   100
 fu7(x, n)   933.936  1078.7590  1343.0666  1146.6095  1203.3410 11592.100   100