R：递归划分迷宫/环境问题和在递归函数中定义收益

问题描述

为了更好地了解R并了解递归的工作原理，我实现了递归除法迷宫生成算法。据我所知，我的实现有效，但仅当我使用超级分配运算符“

因此，对于return（）函数和环境的工作方式，我显然缺少一些东西，但是我无法弄清楚这是什么，或者如何在无需使用全局赋值的情况下使代码工作。我也不确定如何缩小该示例的大小，因为我从未遇到过这样的问题，因此对冗长的代码表示抱歉。

这是有效的代码：

N = 10  # extent x & y
fin = 2 # finish recursion 
maze = array(1,dim = c(N,N))

divide <- function(grid,width,height,fin,xoff = 0,yoff = 0){
set.seed(123)

  # end recursion
  if (width <= fin || height <= fin){
    maze <<- grid   #this is the part i want to get rid of
    return(grid)
  }
  # choose if vertical or horizontal wall
  if (width  < height){ orient = 2 } #horizontal
  else if (height < width ){ orient = 1 } # vertical
  else { orient = sample.int(2,1,TRUE) }

  #  build wall with a passage in it
  if (orient == 2){
    wall <- 2L * sample.int((height-1)/2,TRUE)
    pass <- 2L * sample.int(width/2,TRUE) -1
    build <- 1:width
    build  <- build[-pass] + xoff
    grid[wall + yoff,build] <- 0

  }else {
    wall <-  2L * sample.int((width-1)/2,TRUE)
    pass <-  2L * sample.int(height/2,TRUE)-1
    build <- 1:height
    build  <- build[-pass]  + yoff
    grid[build,wall + xoff] <- 0
  }
  # this is just for plotting,so that the image faces the right direction
  pic <- apply(grid,2,rev)
  image(t(pic))
  Sys.sleep(1.5)

 # recusion in the sub areas
  if (orient == 2)
  {
   # Top & Bottom
    divide(grid = grid,width = width,height = wall,fin = fin,xoff = xoff,yoff = yoff)

# i would expect the following to work when i just pass the grid 
# that has been returned from the function call above (grid = grid)
# but that doesnt work
    divide(grid = maze,height = height - wall,yoff = yoff + wall)
  }
  else
  {
    # Left and Right
   divide(grid = grid,width = wall,height = height,yoff = yoff)

    divide(grid = maze,width = width - wall,xoff = xoff + wall,yoff = yoff)
  }
}

divide(maze,N,fin)

我的目标是通过仅将网格内部交给下一个递归步骤，而不是将其存储在全局对象“迷宫”中，来完成此工作。还是这样一个问题：为什么返回函数不能将网格传递给下一个函数调用？

sessionInfo()
R version 4.0.2 (2020-06-22)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19041)

解决方法

暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！

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maze r r recursion