在R Studio中使用stdin [英] Use stdin from within R studio

问题描述

当我尝试以下操作时:

f<-file("stdin")
lines<-readLines(f)

在Ubuntu上的R-studio中，

我可以输入文本，但是无法终止它. Ctr + C/D，随机敲击键盘无济于事.它只是挂起

from within R-studio on Ubuntu I can input text but unable to terminate it. Ctr+C/D, random hitting keyboard won't help. It simply hangs

到目前为止，我只发现了追随者 如何在R中的stdin中输入EOF? 但那里没有帮助-必须杀死R-studio.

I only found the followin so far How to input EOF in stdin in R? but no help there - had to kill R-studio.

有人解释出什么问题了吗

Anybody have explanation what is wrong?

推荐答案

大概是Rstudio重定向了stdin，因此无法再以"stdin"或"/dev/stdin"的形式正确访问它.但是，stdin()仍然有效.

Presumably, Rstudio is redirecting stdin, so that it cannot be properly accessed as "stdin" or "/dev/stdin" any longer. However, stdin() still works.

我仍然无法真正键入Ctrl + D.但是可以读取固定数量的行:

I was still unable to actually type Ctrl+D. But it is possible to read a fixed number of lines:

> a <- readLines(stdin(), n=2)
Hello
World
> a 
[1] "Hello" "World"

我还发现了一种可以帮助进行交互式调试的hack.假设您的手动示例中最多有10行.然后，您可以

I've also discovered a hack that may help for interactive debugging. Let's say, you have at most 10 lines in your manual examples. Then you can do

> a <- readLines(stdin(), n=10)
abc
def
ghi

# and now just keep pressing ENTER
...

> a <- a[a != ""]
> a
[1] "abc" "def" "ghi"

如果您在可以使用Ctrl + D的环境中运行相同的代码，它也会正确终止输入.

If you run the same code in an environment where Ctrl+D is available, it also properly terminates the input.

注意事项:但stdin()不适用于Rscript:您必须切换回file("stdin").此外，在某些环境中，如果将readLines与n=1结合使用以逐行读取文件，则最终可能会重新打开文件并每次都获得第一行.似乎将所有内容都放入一个文件中并使用例如一次读取整个文件read.table是使用Rstudio开发的一种更强大的方法.

Caveats: but stdin() does not work with Rscript: you'd have to switch back to file("stdin"). Furthermore, in some environments, if you use readLines with n=1 to read the file line-by-line, you may end up reopening the file and getting the first line every time. It seems that putting everything into a file and reading the whole file at once with e.g. read.table is a much more robust way of developing with Rstudio.

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