如何在脚本中包含要从命令行运行的交互式输入

I am trying to write an interactive R script. For example:

我正在尝试编写一个交互式R脚本。例如：

try.R:

try.R：

print("Entr some numbers. >",quote=F)
a = scan(what=double(0))
print a
q()

Now, if I run it on the command line as

现在，如果我在命令行上运行它

$ R --no-save < try.R

It tries to get the stdin from try.R, giving the following error:

它试图从try.R获取stdin，给出以下错误：

> print("Entr some numbers. >",quote=F)
[1] Entr some numbers. >
> a = scan(what=double(0))
1: print a
Error in scan(file, what, nmax, sep, dec, quote, skip, nlines, na.strings,  : 
  scan() expected 'a real', got 'print'
Execution halted

I tried a few other methods but they all give errors. For example:

我尝试了其他一些方法，但都会出错。例如：

$ R CMD BATCH try.R 
$ Rscript try.R

So how do I write an R script that works from the *nix shell command line, and can take in interactive input from the user?

那么如何编写一个可以从* nix shell命令行运行的R脚本，并且可以从用户那里获取交互式输入？

3 个解决方案

#1

Try this:

尝试这个：

cat("What's your name? ")
x <- readLines(file("stdin"),1)
print(x)

Hopefully some variant of that works for you.

希望有些变体适合你。

#2

What worked for me on Windows with RStudio 0.98.945 and R version 3.1.1 was:

在Windows上使用RStudio 0.98.945和R版本3.1.1对我有用的是：

    cat("What's your name? ")
    x <- readLines(con=stdin(),1)
    print(x)

#3

The answer by @Joshua Ulrich is fine for Linux, but hangs under macOS and needs to be terminated using Ctrl-D.

@Joshua Ulrich的答案适用于Linux，但在macOS下挂起并需要使用Ctrl-D终止。

This is a work-around for both Linux and macOS:

这是Linux和macOS的解决方法：

#!/usr/bin/env Rscript

print(system("read -p 'Prompt: ' input; echo $input", intern = TRUE))

#1