忽略tryCatch()中的简单警告/错误

Question

我是一个狂热的粉丝tryCatch().然而,直到今天,我从未真正关注简单和常规警告/错误之间的区别,因此我真的不知道如何处理它们.

实际问题

我想知道的是如何告诉tryCatch(参见帮助文件)简单的警告是正常的,它应该返回结果expr而不是跳转到该warning部分.

您将在下面找到一个可重复的示例

---

不tryCatch>>没有警告

require("forecast")
y   <- ts(c(6178, 7084, 8162, 8462, 9644, 10466, 10748, 9963, 8194, 6848, 7027, 7269, 6775, 7819, 8371, 9069, 10248, 11030, 10882, 10333, 9109, 7685, 7602, 8350, 7829, 8829, 9948, 10638, 11253, 11424, 11391, 10665, 9396, 7775, 7933, 8186, 7444, 8484, 9864, 10252, 12282, 11637, 11577, 12417, 9637, 8094, 9280, 8334, 7899, 9994, 10078, 10801, 12950, 12222, 12246, 13281, 10366, 8730, 9614, 8639, 8772, 10894, 10455, 11179, 10588, 10794, 12770, 13812, 10857, 9290, 10925, 9491, 8919, 11607, 8852, 12537, 14759, 13667, 13731, 15110, 12185, 10645, 12161, 10840, 10436, 13589, 13402, 13103, 14933, 14147, 14057, 16234, 12389, 11595, 12772))
out <- forecast::auto.arima(x=y)
> out
Series: y 
ARIMA(4,1,1)                    

Coefficients:
         ar1      ar2     ar3      ar4      ma1
      0.6768  -0.2142  0.5025  -0.7125  -0.8277
s.e.  0.0749   0.0889  0.0874   0.0735   0.0485

sigma^2 estimated as 915556:  log likelihood=-780.33
AIC=1572.65   AICc=1573.62   BIC=1587.91

tryCatch >>简单的警告

当我用它包装时tryCatch,它会检测到一个简单的警告,它会导致我的expr块被"跳过"而支持该warning部分.因此该函数不返回估计结果,而是返回简单警告.

mod <- tryCatch(
    out <- forecast::auto.arima(x=y),
    error=function(e) {
        print(e)
    },
    warning=function(w) {
        print(w)
    }
)

> mod 
<simpleWarning in kpss.test(x): p-value smaller than printed p-value>

目前的解决方法

if (any(class(mod) == "simpleWarning")) {
    mod <- forecast::auto.arima(x=y)
}

> mod
Series: y 
ARIMA(4,1,1)                    

Coefficients:
         ar1      ar2     ar3      ar4      ma1
      0.6768  -0.2142  0.5025  -0.7125  -0.8277
s.e.  0.0749   0.0889  0.0874   0.0735   0.0485

sigma^2 estimated as 915556:  log likelihood=-780.33
AIC=1572.65   AICc=1573.62   BIC=1587.91

Answer 1

我认为你正在寻找它们之间的区别tryCatch,它捕获一个条件并继续从定义了tryCatch的环境进行评估,相比之下withCallingHandlers,它允许你"处理"一个条件,然后从条件发生的位置继续.看看warning(或帮助页面警告,但那不那么有趣),尤其是线条

    withRestarts({
        .Internal(.signalCondition(cond, message, call))
        .Internal(.dfltWarn(message, call))
    }, muffleWarning = function() NULL)

这表示 - 发出条件信号,但在条件发出信号的地方插入"重启".那你就是

withCallingHandlers({
    warning("curves ahead")
    2
}, warning = function(w) {
    ## what are you going to do with the warning?
    message("warning occurred: ", conditionMessage(w))
    invokeRestart("muffleWarning")
})

虽然withCallingHandlers经常使用警告和tryCatch错误,但没有什么可以阻止人们"处理"错误或捕获警告,如果这是适当的操作.