r - 如何将警告()输出到字符串

Question

当我输入警告()到控制台时，我回来了

Warning message:
In fread(my_directory,  ... :
 C function strtod() returned ERANGE for one or more fields. The first was string input    '4.40589099726375E-309'. It was read using (double)strtold() as numeric

但是，当我输入 as.character(warnings()) 时，我得到:

[1] "fread(my_directory)"

我的目标是将 warning() 中显示的实际消息转换为字符串，以便我可以将其传递给 logwarn logging 中的函数包裹。目前，我正在做 logwarn(warnings(),logger="some_log_file.log")记录我的警告，但它给了 character 不正确的强制我在上面显示的。

请注意，我只能使用 sink但我想坚持 logging包，所以我需要能够纠正强制到 character .

Answer 1

这可能不是您正在寻找的确切答案，但我认为值得一提。

R 有一个全局变量，last.warning ，这就是最后一个警告。调用 names它将以字符串形式返回最后一个警告。这是一个小例子

首先，故意触发警告:

x <- 1:5
if(x == 1) "yes" else "no"
# [1] "yes"
# Warning message:
# In if (x == 1) "yes" else "no" :
#   the condition has length > 1 and only the first element will be used

查看变量 last.warning :

last.warning
# $`the condition has length > 1 and only the first element will be used`
# if (x == 1) "yes" else "no"

现在看看 names(last.warning) .这将警告作为字符串返回:

names(last.warning)
# [1] "the condition has length > 1 and only the first element will be used"