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Possible Duplicate:
Python read a single character from the user

I am looking to be able to control a robot with the arrow keys using python. And my idea was to implement code that looked something like this...

#!/usr/bin/env python
# control a robot using python
exit = 0
while exit == 0:
  keypress = ##get keypress, if no key is pressed, continue##
  if keypress == 'q':
    exit = 1
    break
  elif keypress == KEY_UP:
    ##robot move forward##
  elif keypress == KEY_DOWN:
    ##robot move backward##
print "DONE"

However the problem is that I do not know how to get the users input. And I cannot use a GUI based solution like pygame from what I have found because the robot does not use a display.

Any help is very much appreciated!!

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  • Identical to this question, which has several solutions. Commented May 21, 2012 at 22:05
  • You might want to look into curses. Commented May 21, 2012 at 22:05
  • I was looking at that question, but could not figure out if it was what I was looking for or not because I am looking for a linux solution and that seemed really complicated because of the cross-platform needs. I looked at curses, but does anyone know of a good tutorial on how to use it? The best I could find was the Python Docs and they only went so far. Commented May 21, 2012 at 23:34
  • 1
    There are a lot of answers to this question on SO. One of which explains that just trying to get a couple key press events makes curses a bit of overkill, and that you can simply read from stdin and interpret the keys. stackoverflow.com/a/7264312/496445 Commented May 22, 2012 at 0:06

1 Answer 1

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A simple curses example. See the docs for the curses module for details. 

import curses
stdscr = curses.initscr()
curses.cbreak()
stdscr.keypad(1)

stdscr.addstr(0,10,"Hit 'q' to quit")
stdscr.refresh()

key = ''
while key != ord('q'):
    key = stdscr.getch()
    stdscr.addch(20,25,key)
    stdscr.refresh()
    if key == curses.KEY_UP: 
        stdscr.addstr(2, 20, "Up")
    elif key == curses.KEY_DOWN: 
        stdscr.addstr(3, 20, "Down")

curses.endwin()
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4 Comments

Why is it that two letters get displayed when I hit a letter key once? It looks like getch moves cursor to the right of where addch puts it. Therefore, when I hit the next key, it gets displayed to the left of 20, 25, and then addch displays the same letter at 20, 25, leaving two characters on the screen. I guess getch does not prevent the letter to the right of 20, 25 from being displayed? How can I disable what I entered from being displayed?
allyourcode - add curses.noecho() (after the call to cbreak is good). Then curses won't autoprint the key, only the script will.
Simpler solution is to use sshkeyboard. It requires less coding than curses, and it is a cross platform solution.
@ilon - Post an answer then...

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