R将函数与if语句一起应用于列表中的每个元素 [英] R Apply function with if statements to every elements in list

问题描述

我有一个巨大的列表，下面是 trboot6的样本

I have a huge list, below is a sample of trboot6

更新：我不想删除额外的1或-1。相反，我想将其更改为零。我很抱歉

UPDATE: I do not want to delete the extra "1" or "-1". Instead I want to change it to zero. I am so sorry

dput()
structure(list(`1` = c(-1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1), `2` = c(-1, 
-1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 
-1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1), `3` = c(1, -1, -1, 
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, 
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
-1, -1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1), `4` = c(-1, 
-1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 
-1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 
-1, -1, -1, -1, -1, -1, -1, -1, -1, 1), .Names = c("1", "2", "3", "4"))

将以下内容仅用于说明目的

Putting the below for illustration purpose only

$ 1  : num [1:39] -1 1 -1 -1 -1 -1 -1 -1 -1 1 ...
$ 2  : num [1:46] -1 -1 -1 1 1 1 -1 -1 -1 -1 ...
$ 3  : num [1:48] 1 -1 -1 -1 -1 -1 -1 -1 -1 -1 ...
$ 4  : num [1:43] -1 -1 1 -1 -1 -1 -1 -1 -1 -1 ...

我想要做的是检查每个列表中每对是否有1和-1。对在下面的括号中表示：

What I want to do is check if in each list every pair has 1 and -1. Pairs are represented in brackets in the following:

$ 1  : num [1:39] (-1 1) (-1 -1) (-1 -1) (-1 -1) (-1 1) ...
$ 2  : num [1:46] (-1 -1) (-1 1) (1 1) (-1 -1) (-1 -1) ...
$ 3  : num [1:48] (1 -1) (-1 -1) (-1 -1) (-1 -1) (-1 -1) ...
$ 4  : num [1:43] (-1 -1) (1 -1) (-1 -1) (-1 -1) (-1 -1) ...

如果该对没有1和-1那么，我想要将第二个相同的数字更改为零，即如果该对是（1 1），我将第二个1更改为零以获得'（1 0）'。如果再次有1，我也改变这个1。然后，如果有一个-1，它将与第一个1配对。

If the pair does not have 1 and -1 then, I want to change the second same number to zero, that is if the pair is (1 1), I change the second 1 to zero to get '(1 0)'. If there is 1 again, I change this 1 too. Then if there is a -1, it will pair with the first 1.

为了更好的编码，我使用了总和应始终保持在-2和2之间的逻辑对于存在的对。对不能是（1，-1）（ - 1,1）或（1，-1）（1，-1）。因此，如果余额<-2或> 2，则必须删除最新的数字。

To better code, I used the logic that the sum should always remain between -2 and 2 for the pairs to exist. Pair cant be (1,-1) (-1,1) or (1,-1) (1,-1). So if the balance goes <-2 or >2, the latest number has to be deleted.

以下是我的上述逻辑代码：

Here is my code for the above logic:

balboot<-0
fboot<- function(x) {
  ifelse(x==-1,balboot<-balbbot-1,balboot<-balboot+1)
  if(balboot==-2){x<-0 
  balboot=-1} 
  if(balboot==2){x<-0 
  balboot=1}
  return(fboot)
}
rdtp<-lapply(trboot6, FUN=fboot)

运行此操作后，我收到警告：

After running this, I get the warning:

In if (x == 1) { ... :
  the condition has length > 1 and only the first element will be used

预期输出：

list '1': -1, 1, -1, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
list '2': -1, 0, 0, 1, 1, 0, -1, -1,0, 0, 0, 0, 1, 1, -1, -1, 0, 0, 0, 1, 1, 0, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0

提前感谢您的帮助。

推荐答案

我们可以定义一个接收向量 x 的函数，并检查对。如果该对不总和为0，则将该对中的第二项替换为0，然后继续沿向量检查。我们使用 i 和 j 作为我们的迭代器。

We can define a function that takes in a vector x, and checks for "pairs". If the pair doesn't sum to 0, it replaces the second item of the pair with 0, and then keeps checking along the vector. We use i and j as our iterators.

good_pairs <- function(x){

    i <- 1
    j <- 2
    keepgoing <- TRUE

    while(keepgoing){
        #grab a pair and sum it
        pair <- x[c(i, j)]
        pair_sum <- sum(pair)

        while(pair_sum != 0){ #continue iterating until sum == 0
            #replace i + 1 element with 0
            x[j] <- 0
            j <- j + 1
            #break if we've run out of elements
            if(is.na(x[j])){
                break
            }else{
            #check the pair
            pair <- x[c(i, j)]
            pair_sum <- sum(pair)
            }

        }
        #increment
        i <- j + 1   
        j <- j + 2
        keepgoing <- (length(x) > i)

    }
    x
}

lapply(trboot6, good_pairs)
[[1]]
 [1] -1  1 -1  0  0  0  0  0  0  1 -1  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0

[[2]]
 [1] -1  0  0  1  1  0 -1 -1  0  0  0  0  1  1 -1 -1  0  0  0  1  1  0 -1 -1  0  0  0  0  0  0  0  0  0  1  1 -1 -1  0  0  0  0  0  0  0
[45]  0  0

[[3]]
 [1]  1 -1 -1  0  0  0  0  0  0  0  0  0  0  1 -1  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  1 -1  0  0  0  0
[45]  0  0  0  0

[[4]]
 [1] -1  0  1 -1  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  1  1 -1 -1  0  0  1 -1  0  0  0  0  0  0  0  0  0  0  1

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