raw_input and timeout

Question

I have thise huge code that I'm going to implement . Before I start that, I want to do a raw_input('Enter something: .'). I want it to sleep for 3 secs and if there's no input, then cancel the raw-input prompt and run the rest of the code. Then the code loops and implements the raw_input again.

I want it so that if somedoes put a raw_input in like 'q', then I want the loop to break.

Is there a simple way to do this? I've been stuck on this forever.

Thank You.

Answer 1

There are many ways to do this on Unix:

http://stackoverflow.com/questions/1335507/keyboard-input-with-timeout-in-python

but you probably don't want that...?

Answer 2

There's an easy solution that doesn't use threads (at least not explicitly): use select to know when there's something to be read from stdin:

import sys
from select import select

timeout = 10
print "Enter something:",
rlist, _, _ = select([sys.stdin], [], [], timeout)
if rlist:
    s = sys.stdin.readline()
    print s
else:
    print "No input. Moving on..."

Answer 3

If you're working on Windows you can try the following:

import sys, time, msvcrt

def readInput( caption, default, timeout = 5):
    start_time = time.time()
    sys.stdout.write('%s(%s):'%(caption, default));
    input = ''
    while True:
        if msvcrt.kbhit():
            chr = msvcrt.getche()
            if ord(chr) == 13: # enter_key
                break
            elif ord(chr) >= 32: #space_char
                input += chr
        if len(input) == 0 and (time.time() - start_time) > timeout:
            break

    print ''  # needed to move to next line
    if len(input) > 0:
        return input
    else:
        return default

# and some examples of usage
ans = readInput('Please type a name', 'john') 
print 'The name is %s' % ans
ans = readInput('Please enter a number', 10 ) 
print 'The number is %s' % ans