r - R : Function returns both error and warning - store both with tryCatch()

Question

我在readLines()中使用[R]，对于某些URL，它会给我错误以及警告消息:

Error in file(con, "r") : cannot open the connection
In addition: Warning message:
In file(con, "r") : cannot open: HTTP status was '401 Unauthorized'

如您所见，该函数在警告中同时返回一般错误和更具体的解释。目前，我正在使用 tryCatch()和一些行来使用 conditionMessage()打印和存储这些错误。但是，这只存储一般的非信息性错误消息，而实际上我对警告文本更感兴趣。如何存储两者？

工作示例:

errorlist <- NULL

for(i in 1:10){
tryCatch({
readLines("http://www.googl1.com/") # this URL does not exist
}, error = function(e){yy
  print(conditionMessage(e))
  assign("errorlist", c(errorlist, conditionMessage(e)), envir = .GlobalEnv)
})}

所需的结果将是这样的:

      [,1]                     [,2]                                              
 [1,] "cannot open connection" "The server name or address could not be resolved"
 [2,] "cannot open connection" "The server name or address could not be resolved"
 [3,] "cannot open connection" "The server name or address could not be resolved"
 [4,] "cannot open connection" "The server name or address could not be resolved"
 [5,] "cannot open connection" "The server name or address could not be resolved"
 [6,] "cannot open connection" "The server name or address could not be resolved"
 [7,] "cannot open connection" "The server name or address could not be resolved"
 [8,] "cannot open connection" "The server name or address could not be resolved"
 [9,] "cannot open connection" "The server name or address could not be resolved"
[10,] "cannot open connection" "The server name or address could not be resolved"

Answer 1

您可以通过以下方式将警告变为错误

options(warn=2)

另一方面，这只会在 tryCatch中返回警告(作为错误)。