How to manage real time input with periodic updates

Question

I have a block at position (0,0). Periodically (say every 1 second) the y-coordinate of the block will randomly get updated by +/-1.

And every time the user also inputs a character (+/-) the x-coordinate will be updated by +/-1 as the user has inputted.

If it was only the x coord, I could create a while loop, that runs into the next iteration when input() gets a value.

But how can I deal with both the periodic update as well as the real time input (which can come at any time?)

If you're asking "how do I poll for keyboard input without blocking indefinitely until the user hits Enter?", [getch](https://docs.python.org/3/library/msvcrt.html#msvcrt.getch) may be an option. — Kevin, Aug 14 '17 at 16:52
Possible duplicate of [What's the simplest way of detecting keyboard input in python from the terminal?](https://stackoverflow.com/questions/13207678/whats-the-simplest-way-of-detecting-keyboard-input-in-python-from-the-terminal) — EsotericVoid, Aug 14 '17 at 16:58
@Kevin Ive played simple terminal games (like tetris) written in Python where the updates (in the case of tetris, the main shape going down by one unit) happens every `x` second or so, but the shape can be moved sidewards whenever the user inputs a character (using getch I guess). The updates can be done periodically using some time related module. But how to integrate that with the user's inputs? — Ind Oubt, Aug 14 '17 at 16:59

score 1 · Accepted Answer · answered Aug 14 '17 at 20:50

Threading is your friend:

import time
from threading import Thread


# This defines the thread that handles console input
class UserInputThread(Thread):
    def __init__ (self):
        Thread.__init__(self)

    # Process user input here:
    def run(self):
        while True:
            text = input("input: ")
            print("You said", text)
            # Exit the thread
            if text == "exit":
                return


console_thread = UserInputThread()
console_thread.start()

while True:
    time.sleep(5)
    print("function")
    # If the thread is dead, the programme will exit when the current iteration of the while loop ends.
    if not console_thread.is_alive():
        break

UserInputThread runs in the background and handles the user input. print("function") could be any logic you need to do in the main thread.

How to manage real time input with periodic updates

1 Answers1