我正在编写一个带有以下形式的tryCatch()
循环的R包,其中我首先尝试使用容易出错的方法拟合模型,但如果第一次失败则使用更安全的方法:
# this function adds 2 to x
safe_function = function(x) {
tryCatch( {
# try to add 2 to x in a stupid way that breaks
new.value = x + "2"
}, error = function(err) {
message("Initial attempt failed. Trying another method.")
# needs to be superassignment because inside fn
assign( x = "new.value",
value = x + 2,
envir=globalenv() )
} )
return(new.value)
}
safe_function(2)
此示例按预期工作。但是,使用assign
会在检查包的CRAN就绪时触发注释:
Found the following assignments to the global environment
如果我用assign
替换<<-
,就会出现类似的问题。我能做什么?
我不确定你为什么要在这里使用全局范围。你可以从try/catch
返回值。
safe_function = function(x) {
new.value <- tryCatch( {
# try to add 2 to x in a stupid way that breaks
x + "2"
}, error = function(err) {
message("Initial attempt failed. Trying another method.")
x + 2
} )
return(new.value)
}