Description
Wait for a Key Press in a Terminal.
Description
Wait for a single key press at the 'R' prompt. This works in terminals, but does not currently work in the 'Windows' 'GUI', the 'OS X' 'GUI' ('R.app'), in 'Emacs' 'ESS', in an 'Emacs' shell buffer or in 'R Studio'. In these cases 'keypress' stops with an error message.
README.md
keypress
Read a single key press from the terminal
Installation
install.packages("keypress")
Usage
> has_keypress_support()
[1] TRUE
> x <- keypress()
> cat("You pressed key", x, "\n")
You pressed key h
Support
This is unfortunately impossible to do in
- RStudio,
- R.app (the builtin OSX GUI),
- RGui (the builtin Windows GUI),
- Emacs ESS, or
- if
stdin()is not a terminal.
In other words, it pretty much only works interactively, in a terminal. The terminal can be pretty much any Linux, OSX, or other Unix terminal or Windows cmd (also called RTerm in R).
Keys
Note that not all keys are supported, in particular most of the modifiers (alt, shift, etc.) are not. Supported special keys are:
- Arrow keys:
up,down,right,left. Available on most keyboards. - Function keys: from
f1tof12. Available on most keyboards. - Other special keys:
enter,backspace,escape,tab. - Some key combinations with the
CONTROLkey:ctrl-a,ctrl-b,ctrl-c,ctrl-d,ctrl-e,ctrl-f,ctrl-h,ctrl-k,ctrl-l,ctrl-n,ctrl-p,ctrl-t,ctrl-u,ctrl-w. - Keys typically not availale on OS X keyboards:
home,end,insert,delete,pageup,pagedown. - On Linux and OS X Unicode characters are supported, but not (yet) on Windows. Unicode characters are returned UTF-8 encoded.
License
MIT © Gábor Csárdi.