在 R 中使用 tryCatch 抑制警告 [英] Suppress warnings using tryCatch in R

问题描述

编写一个 tryCatch 来处理错误值但忽略警告.举个例子

Write a tryCatch that will handle an error value but will ignore a warning. As an example

foo <- function(x) {
  if (x == 1) {
    warning('Warning')
  } else if (x == 0) {
    stop('Error')
  }
  return(1)
}

bar <- function(x){
  tryCatch(
    expr    = foo(x),
    error   = identity,
    warning = function(w) invokeRestart("muffleWarning")
  )
}

所以 foo 会在传递 0 时警告您，传递 1 时会出错. bar 的目的是传递 0 时会出现错误，但它会抑制 bar 生成的警告，如果你传递一个 1. invokeRestart("muffleWarning") 命令来自 suppressWarnings 的定义.它在我这里的建筑中不起作用，我不知道为什么.(具有讽刺意味的是，它会生成一个错误，因此尝试成功将我不想要的警告升级为我无法解释的错误.)

So foo warns you if you pass a 0, and errors if you pass a 1. The intent of bar is that you get an error if you pass a 0, but it suppresses the warning generated by bar if you pass a 1. The invokeRestart("muffleWarning") command comes from the definition of suppressWarnings. It does not work in the construction I have here and I do not know why. (Ironically it generates an error, so trying that successfully escalated a warning I didn't want into an error that I can't interpret.)

bar 的这个定义会起作用

bar <- function(x){
  tryCatch(
    expr    = foo(x),
    error   = SomeFunctionThatDoesNotMatter,
    warning = function(w){suppressWarnings(foo(x))}
  )
}

bar 完全符合我的要求，但它以一种可能很糟糕的方式做到了.想象一下，我有 expr = lapply(X=1:50, ...) 而不是 expr = foo(x) 并且 expr = lapply(X=1:50, ...)code>FUN 需要一个小时才能运行.如果 X[50] 生成唯一的警告，那么我的运行时间会从 50 小时增加一倍到 100 小时(糟糕).

bar does exactly what I want it to, but it does it in a potentially terrible way. Imagine that instead of expr = foo(x) as I have here, that I have expr = lapply(X=1:50, ...) and that the FUN takes an hour to run. If X[50] generates the only warning then my run time has double from 50 hours to 100 hours (yuck).

1. 为什么 invokeRestart("muffleWarning") 在我上面的例子中不起作用?
2. 在使用 tryCatch 时，应该为 warning 分配什么功能，以便让代码继续运行并抑制生成的警告?

1. Why does invokeRestart("muffleWarning") not work in my example above?
2. When using tryCatch, what function should be assigned to warning in order to allow the code to simply keep running and suppress the warnings that are generated?

感谢阅读！

推荐答案

在遵循 nrussell 的直觉之后，我遇到了这个问题.解决办法是替换通用的

I ran into this problem after following nrussell's intuition. The solution is to replace the generic

tryCatch({
  some_fn()
}, warning = function(w) {
  print(paste('warning:', w))
}, error = function(e) {
  print(paste('error:', e))
})

与

tryCatch({
  some_fn()
}, error = function(e) {
  print(paste('error:', e))
})

这种格式/语法对我有用.您可以轻松地将其包含在您需要的函数中

This format/syntax has worked for me. You could easily enclose it in a function like you need to

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