Hi It has taken me longer than I thought to get back to this topic. tut. Anyway thanks. I wondered why array was being mentioned ha ha So have I got this correct in that when I run a turtle program I am in fact using this forever loop, so I do not need to use a while True loop at all really in a turtle gui program?
> To: tutor@python.org > From: __pete...@web.de > Date: Tue, 11 Feb 2014 14:01:47 +0100 > Subject: Re: [Tutor] can I make a while loop true again > > Ian D wrote: > >> Thanks for the help on the last one. >> >> Is it possible to restart a while loop? This doesn't work at all (surprise >> surprise) >> >> import turtle as t >> >> def start(): >> global more >> more = True >> >> def stop(): >> global more >> more = False >> >> more = True >> >> while True: >> while more: >> >> t.onkey(stop, "space") >> t.onkey(start, "Up") >> t.fd(1) >> t.listen() > > When you want your script to work like a typical GUI application you will > soon reach the limits with turtle. turtle tries hard to hide it, but GUIs > have an independent loop permanently running listening to user events and > small functions to respond these events. > > To have the turtle start and stop I came up with the following which looks > similar to normal GUI code. Instead of the explicit loop there is a function > `step_forward` that may or may not reschedule itself depending on the state > of the `running` flag. > > > > import turtle > > def step_forward(): > if running: > turtle.forward(5) > # call step_forward() again after 100 milliseconds: > turtle.ontimer(step_forward, 100) > > def start(): > global running > > if not running: > running = True > step_forward() > > def turn_left(): > turtle.left(10) > > def turn_right(): > turtle.right(10) > > def stop(): > global running > running = False > > running = False > > turtle.delay(0) > turtle.onkey(start, "Up") > turtle.onkey(turn_left, "Left") > turtle.onkey(turn_right, "Right") > turtle.onkey(stop, "space") > > turtle.listen() > turtle.mainloop() > > As a bonus the turtle changes its direction when you hit the left or right > array. > > _______________________________________________ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
