警告消息始终以与警告无关的块形式出现在RStudio笔记本中 [英] Warning messages keep appearing in RStudio notebooks in chunks unrelated to the warnings

问题描述

我开始使用RStudio笔记本电脑，但我仍在尝试了解某些​​功能的工作原理. 我不明白为什么在执行与该消息完全无关的代码时，为什么会保留某些产生的警告消息并出现这些警告消息.例如，我有一个包含多个块的文档，其中最后一个产生警告

I am starting to use RStudio notebooks, and I am still trying to understand how some of the things work. I do not understand why some produced warning messages are kept and appear when executing code that is completely unrelated to the message. For instance, I have a document with several chunks, where the last of them produces the warning

> warnings()
Warning messages:
1: Unknown or uninitialised column: 'perc.goal.met.period'.
2: Unknown or uninitialised column: 'perc.goal.met.period'.
3: Unknown or uninitialised column: 'perc.goal.met.period'.
4: Unknown or uninitialised column: 'perc.goal.met.period'.
5: Unknown or uninitialised column: 'perc.goal.met.period'.
6: Unknown or uninitialised column: 'perc.goal.met.period'.
7: Unknown or uninitialised column: 'perc.goal.met.period'.
8: Unknown or uninitialised column: 'perc.goal.met.period'.
9: Unknown or uninitialised column: 'perc.goal.met.period'.
10: Unknown or uninitialised column: 'perc.goal.met.period'.
11: Unknown or uninitialised column: 'perc.goal.met.period'.
12: Unknown or uninitialised column: 'perc.goal.met.period'.
13: Unknown or uninitialised column: 'perc.goal.met.period'.
14: Unknown or uninitialised column: 'perc.goal.met.period'.
15: Unknown or uninitialised column: 'perc.goal.met.period'.
16: Unknown or uninitialised column: 'perc.goal.met.period'.
17: Unknown or uninitialised column: 'perc.goal.met.period'.
18: Unknown or uninitialised column: 'perc.goal.met.period'.
19: Unknown or uninitialised column: 'perc.goal.met.period'.
20: Unknown or uninitialised column: 'perc.goal.met.period'.
21: Unknown or uninitialised column: 'perc.goal.met.period'.
22: Unknown or uninitialised column: 'perc.goal.met.period'.
23: Unknown or uninitialised column: 'perc.goal.met.period'.
24: Unknown or uninitialised column: 'perc.goal.met.period'.
25: Unknown or uninitialised column: 'perc.goal.met.period'.
26: Unknown or uninitialised column: 'perc.goal.met.period'.
27: Unknown or uninitialised column: 'perc.goal.met.period'.
28: Unknown or uninitialised column: 'perc.goal.met.period'.
29: Unknown or uninitialised column: 'perc.goal.met.period'.
30: Unknown or uninitialised column: 'perc.goal.met.period'.
There were 30 warnings (use warnings() to see them)

我可以接受该警告.但是后来，我以为我会向第一个块(我在其中加载它们)加载一个额外的库.运行该块后，我得到:

I am ok with that warning. But later, I thought I would load one additional library to the first of the chunks (where I load them). After running that chunk, I get:

```{r echo=F, message=F, warnings=F, include=F}
# Load libraries
library(rgdal)
library(raster)
library(openxlsx)
library(tidyverse)
library(dplyr)
library(magrittr)
library(ggplot2)
library(rasterVis)
```
There were 30 warnings (use warnings() to see them)

如果我看到警告，则它们是我之前打印的警告. 我为什么在这里见到他们?我还在其他与变量perc.goal.met.period不相关的块中也看到了这一点.如果我看到警告，它们将在一段时间内停止出现，但在我仍然无法预料的时刻，它们最终将在某个时候再次出现.

If I see the warnings, they are those I printed before. Why am I seeing them here? I am seeing this also in other chunks also unrelated to the variable perc.goal.met.period. If I see the warnings, they will stop appearing for a while, but at a moment that I am still not able to anticipate, they will eventually reappear at some point.

对此行为是否有合乎逻辑的解释?非常感谢您的帮助！

Is there a logical explanation for this behaviour? Thanks a lot for your help!

推荐答案

您将看到警告消息，直到将其清除.运行warnings()函数不会执行此操作. 要清除警告，您可以执行以下命令:

You will see warning messages until you clear them out. Running warnings() function does not do that. To clear warnings you can execute the following command:

assign("last.warning", NULL, envir = baseenv())

尽管，最好的方法是修复代码，以免产生警告.解决它的一种方法是在R中使用tryCatch().

The best approach though is to fix your code so the warnings are not produced. One way to deal with it is to use tryCatch() in R.

您还可以使用supressWarnings()功能禁用所有警告，但是不建议您这样做，因为这会阻止您看到其中的任何警告.

You can also disable all warnings by using supressWarnings() function, but this is not recommended since this will prevent you to see any of them.

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