raw_input and break

[Peter Otten]

input/ldompeling at casema.nl wrote:

> In reply to "Peter Otten" who wrote the following:
> 
>> input/ldompeling at casema.nl wrote:
>> 
>> > >   choices = raw_input("letter s to stop:")
>> > 
>> > Oh no, this is not what I want. Now it is waiting for input when its go
>> > further with the script. Because I have an while True: so I want that
>> > the script go's continue only when I press a key then it must stop the
>> > script.
>> 
>> Solutions to that problem are OS-dependent. For Unix terminals
>> 
>> https://docs.python.org/2/faq/
>> library.html#how-do-i-get-a-single-keypress-at-a-time
>> 
>> shows one way which I used to write the contextmanager below:
>> 
>> $ cat capture_key.py
>> import termios, fcntl, sys, os
>> 
>> from contextlib import contextmanager
>> 
>> 
>> @contextmanager
>> def nonblocking(stdin=None):
>>     if stdin is None:
>>         stdin = sys.stdin
>> 
>>     fd = sys.stdin.fileno()
>> 
>>     oldterm = termios.tcgetattr(fd)
>>     newattr = termios.tcgetattr(fd)
>>     newattr[3] = newattr[3] & ~termios.ICANON & ~termios.ECHO
>>     termios.tcsetattr(fd, termios.TCSANOW, newattr)
>> 
>>     oldflags = fcntl.fcntl(fd, fcntl.F_GETFL)
> Thanks for the reply. Is there no easy way to do so in python ?

If you are asking for a ready-made function in the standard library, I don't 
know one and I don't think there is one (there are recipes that work on top 
of curses though).

> I am using the raspberry pi with Wheezy and for the robot the GoPiGo which
> is connected on the raspberry pi. The GoPiGo board has his own code like:
> fwd()="forward" bwd()="backward" right()="right" left="left" and so on. I
> am just a dummie with python.

The code in capture_key.py may look a bit scary, but just as I took it 
without bothering the details you can take the resulting module without 
caring about the code in it. Alternatively you can search 

https://pypi.python.org

for a solution that you prefer.