raw_input and timeout

Question

I want to do a raw_input('Enter something: .'). I want it to sleep for 3 seconds and if there's no input, then cancel the prompt and run the rest of the code. Then the code loops and implements the raw_input again. I also want it to break if the user inputs something like 'q'.

Answer 1

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..."

Edit[0]: apparently this won't work on Windows, since the underlying implementation of select() requires a socket, and sys.stdin isn't. Thanks for the heads-up, @Fookatchu.

Answer 2

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 

Answer 3

I have some code which makes a countdown app with a tkinter entry box and button so they can enter something and hit the button, if the timer runs out the tkinter window closes and tells them they ran out of time. I think most other solutions to this problem don't have a window which pops up so thought id add to the list :)

with raw_input() or input(), it isn't possible as it stops at the input section, until it receives input, then it carries on...

I have taken some code from the following link: Making a countdown timer with Python and Tkinter?

I used Brian Oakley's answer to this problem and added the entrybox etc.

import tkinter as tk

class ExampleApp(tk.Tk):

    def __init__(self):
        tk.Tk.__init__(self)
        def well():
            whatis = entrybox.get()
            if whatis == "": # Here you can check for what the input should be, e.g. letters only etc.
                print ("You didn't enter anything...")
            else:
                print ("AWESOME WORK DUDE")
            app.destroy()
        global label2
        label2 = tk.Button(text = "quick, enter something and click here (the countdown timer is below)", command = well)
        label2.pack()
        entrybox = tk.Entry()
        entrybox.pack()
        self.label = tk.Label(self, text="", width=10)
        self.label.pack()
        self.remaining = 0
        self.countdown(10)

    def countdown(self, remaining = None):
        if remaining is not None:
            self.remaining = remaining

        if self.remaining <= 0:
            app.destroy()
            print ("OUT OF TIME")


        else:
            self.label.configure(text="%d" % self.remaining)
            self.remaining = self.remaining - 1
            self.after(1000, self.countdown)

if __name__ == "__main__":
    app = ExampleApp()
    app.mainloop()

I know what I added was a bit lazy but it works and it is an example only

This code works for Windows with Pyscripter 3.3

Answer 4

For rbp's answer:

To account for input equal to a Carriage Return simply add a nested condition:

if rlist:
    s = sys.stdin.readline()
    print s
    if s == '':
        s = pycreatordefaultvalue