R嵌套循环只返回最后一次迭代 [英] R nested loop returning only the last iteration

问题描述

我试图使用嵌套for循环来复制实验室存储系统中使用的81位cryobox。下面的代码说明了使用3位盒子的问题：

$ $ $ $ $ $ $ $ c $ u $ u_random_df < - as.data.frame（c（seq（从= 10到= 12 by = 1）））
boxcells< - vector（）
cell_placeholder< - as.data.frame（c（seq（from = 1，to = 3通过= 1）））
为（I在1：3）{
#boxcells< - paste0（ NEW，的sprintf（ ％04D，as.numeric（urine_random_df [I， ]）））
。对于（j在1：nrow（cell_placeholder））{
boxcells< - C（boxcells，糊剂（paste0（ NEW，的sprintf（ ％04D，as.numeric （尿尿液_df [i，]））），cell_placeholder [j，]，sep = - ））
}

}


boxcells < - data.frame（boxcells）
names（boxcells）< - box cell
boxcells

上面的结果是：

pre code $ box
1 NEW0010-1
2 NEW0010-2
3 NEW0010-3
4 NEW0011-1
5 NEW0011-2
6 NEW0011-3
7 NEW0012-1
8 NEW0012-2
9 NEW0012-3

但是，我想将单元格分组到它们各自的框中，如下所示：

pre>
1 NEW0010
2 NEW0010-1
3 NEW0010-2
3 NEW0010-3
4 NEW0011
5 NEW0011-1
6 NEW0011 -2
7 NEW0011-3
8 NEW0012
9 NEW0012-1
10 NEW0012-2
11 NEW0012-3


我试图通过添加 boxcells < - paste0（NEW，sprintf（％04d，as .nu​​meric（urine_random_df [i，]）））在外层循环中。当我用这个代码重新运行代码时，我得到的只是最后一个框：

pre code $ box b
1 NEW0012
2 NEW0012-1
3 NEW0012-2
4 NEW0012-3

循环的每一次迭代都会清除最后一个循环，在完成整个循环后，只剩下最后一个循环。我在这里找到了一个现有的线程，这表明在循环之外移动初始化语句。然而，在这种情况下，初始化语句 urine_random_df ... ， boxcells ... 和 cell_placeholder ... 已经在循环之外。想一想

解决方案

我可以考虑非常少见的情况，当你为在R中循环，即使单个为循环也是非常罕见的。

类似

 温度<  -  expand.grid（sprintf的（ ％04D，as.numeric（urine_random_df [1] ）），c（，paste0（ - ，cell_placeholder [，1]）））
 boxcells<  -  data.frame（box_cells = paste0（NEW，paste0（temp [，1]， temp $，
 
 
 
 
 
 
 
 
 
 
 
 
 $ $ b 
  box_cells 
 1 NEW0010 
 2 NEW0011 
 3 NEW0012 
 4 NEW0010-1 
 5 NEW0011-1 
 6 NEW0012-1 
 7 NEW0010-2 
 8 NEW0011-2 
 9 NEW0012-2 
 10 NEW0010-3 
 11 NEW0011-3 
 12 NEW0012-3 
  
如果您不喜欢订单，您可以按
  boxcells<  -  data.frame（box_cells = boxcells [order（as.numeric（substr（boxcells $ box_cel 6,7））），]）
 
 box_cells 
 1 NEW0010 
 2 NEW0010-1 
 3 NEW0010-2 
 4 NEW0010-3 
 5 NEW0011 
 6 NEW0011-1 
 7 NEW0011-2 
 8 NEW0011-3 
 9 NEW0012 
 10 NEW0012-1 
 11 NEW0012 -2 
 12 NEW0012-3 
  
 
I am trying to replicate 81-place cryoboxes used in lab storage system using a nested for loop. The following code illustrates the problem using 3-place boxes:
urine_random_df <- as.data.frame(c(seq(from = 10, to = 12, by = 1)))
boxcells <- vector()
cell_placeholder <- as.data.frame(c(seq(from = 1, to = 3, by = 1)))
for (i in 1: 3){
        #boxcells <- paste0("NEW", sprintf("%04d", as.numeric(urine_random_df[i,])))
        for (j in 1: nrow(cell_placeholder)){
                boxcells <- c(boxcells, paste(paste0("NEW", sprintf("%04d", as.numeric(urine_random_df[i,]))), cell_placeholder[j,], sep = "-"))        
        }

}


boxcells <- data.frame(boxcells)
names(boxcells) <- "box cells"
boxcells
The result of above is:
box cells
1 NEW0010-1
2 NEW0010-2
3 NEW0010-3
4 NEW0011-1
5 NEW0011-2
6 NEW0011-3
7 NEW0012-1
8 NEW0012-2
9 NEW0012-3
However, I would like to group the cells under their respective boxes like so:
   box cells
1  NEW0010
2  NEW0010-1
3  NEW0010-2
3  NEW0010-3
4  NEW0011
5  NEW0011-1
6  NEW0011-2
7  NEW0011-3
8  NEW0012
9  NEW0012-1
10 NEW0012-2
11 NEW0012-3
I tried to achieve this by adding boxcells <- paste0("NEW", sprintf("%04d", as.numeric(urine_random_df[i,]))) in the outer loop. When I re-ran the code with this piece, I get only the last box like so:
  box cells
1   NEW0012
2 NEW0012-1
3 NEW0012-2
4 NEW0012-3
It appears each iteration of the loop erases the last such that upon completion of the entire loop, only the last box remains. I found an existing thread here which suggests moving the "initialisation statements" outside the loop. However, in this case, the initialisation statements urine_random_df..., boxcells... and cell_placeholder... are already outside the loop. Thoughts?
解决方案
I can think of very rare situations when you would do a nested for loop in R, even single for loop is very rare.

I would solve this by doing something like
temp <- expand.grid(sprintf("%04d", as.numeric(urine_random_df[,1])), c("", paste0("-",cell_placeholder[, 1])))
boxcells <- data.frame(box_cells = paste0("NEW", paste0(temp[, 1], temp[, 2])))
Which will return
   box_cells
1    NEW0010
2    NEW0011
3    NEW0012
4  NEW0010-1
5  NEW0011-1
6  NEW0012-1
7  NEW0010-2
8  NEW0011-2
9  NEW0012-2
10 NEW0010-3
11 NEW0011-3
12 NEW0012-3
If you don't like the order, you could reorder by
boxcells <- data.frame(box_cells = boxcells[order(as.numeric(substr(boxcells$box_cells, 6,7))), ])

   box_cells
1    NEW0010
2  NEW0010-1
3  NEW0010-2
4  NEW0010-3
5    NEW0011
6  NEW0011-1
7  NEW0011-2
8  NEW0011-3
9    NEW0012
10 NEW0012-1
11 NEW0012-2
12 NEW0012-3


                        
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