此R代码生成一个缺少的值，其中存在TRUE/FALSE错误

此代码生成一个错误：

while diff

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现在我发现这通常是因为while中的条件计算为NA，因此while无法检查TRUE/FALSE。但在这种情况下，我真的看不出错误是什么。

据我所知，ppm永远不会在while{}中初始化因为‘j’将永远不会= 0。我也看不到“i”在哪里递增。您可以考虑提供头列表$ppm。

我想我可能错了，因为你从未描述过目标，但也许你真正想要的是：

diff.ppm <- diff(list$ppm)
diff.ppm[1:which.min(diff.ppm >= limit)]

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第一次通过while循环时：

j是1，ppm[1]被设置为列表$ppm的第i个元素 j增加到2 j现在大于1，所以取ppm[2]与ppm[1]之间的差值，ppm[2]仍然是NA，因为ppm被初始化为NA，并且ppm[2]还没有被触及；结果是NA 现在回到while循环的顶部，比较diff Now NA和固定在0.05的限制…动臂

i <- 1
j <- 1
limit <- 0.05
diff <- 0     ## diff() is a built-in, probably avoid ...
ppm <- rep(NA,20)
list <- data.frame(ppm=1:10)  ## list is a built-in, probably avoid ...
while(i[1]<=nrow(list))   ## why i[1] ??? why not just i ???
{
  while(diff < limit) ##This is where the error is occurring
  {
    if(j==0)  ## as DWin says: never true, j is initialized to 1
       ppm <- rep(NA,length(ppm))
    ppm[j] <- list$ppm[i]      
    j <- j+1
    if(j > 1) {  ## always true if j is initialized to 1 and incremented the first time
      diff <- ppm[j]-ppm[j-1]  ## will be NA if ppm[j-1] is NA
      cat(j,ppm[j-1],ppm[j],diff,"\n")  ## debugging statement!
     }
  }
  print(ppm)
}

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i <- 1
j <- 1
limit <- 0.05
diff <- 0     ## diff() is a built-in, probably avoid ...
ppm <- rep(NA,20)
list <- data.frame(ppm=1:10)  ## list is a built-in, probably avoid ...
while(i[1]<=nrow(list))   ## why i[1] ??? why not just i ???
{
  while(diff < limit) ##This is where the error is occurring
  {
    if(j==0)  ## as DWin says: never true, j is initialized to 1
       ppm <- rep(NA,length(ppm))
    ppm[j] <- list$ppm[i]      
    j <- j+1
    if(j > 1) {  ## always true if j is initialized to 1 and incremented the first time
      diff <- ppm[j]-ppm[j-1]  ## will be NA if ppm[j-1] is NA
      cat(j,ppm[j-1],ppm[j],diff,"\n")  ## debugging statement!
     }
  }
  print(ppm)
}