Asked  6 Months ago    Answers:  2   Viewed   19 times

I am trying to make a simple IRC client in Python (as kind of a project while I learn the language).

I have a loop that I use to receive and parse what the IRC server sends me, but if I use raw_input to input stuff, it stops the loop dead in its tracks until I input something (obviously).

How can I input something without the loop stopping?

(I don't think I need to post the code, I just want to input something without the while 1: loop stopping.)

Edit: I'm on Windows.

 Answers

82

For Windows, console only, use the msvcrt module:

import msvcrt

num = 0
done = False
while not done:
    print(num)
    num += 1

    if msvcrt.kbhit():
        print "you pressed",msvcrt.getch(),"so now i will quit"
        done = True

For Linux, this article describes the following solution, it requires the termios module:

import sys
import select
import tty
import termios

def isData():
    return select.select([sys.stdin], [], [], 0) == ([sys.stdin], [], [])

old_settings = termios.tcgetattr(sys.stdin)
try:
    tty.setcbreak(sys.stdin.fileno())

    i = 0
    while 1:
        print(i)
        i += 1

        if isData():
            c = sys.stdin.read(1)
            if c == 'x1b':         # x1b is ESC
                break

finally:
    termios.tcsetattr(sys.stdin, termios.TCSADRAIN, old_settings)

For cross platform, or in case you want a GUI as well, you can use Pygame:

import pygame
from pygame.locals import *

def display(str):
    text = font.render(str, True, (255, 255, 255), (159, 182, 205))
    textRect = text.get_rect()
    textRect.centerx = screen.get_rect().centerx
    textRect.centery = screen.get_rect().centery

    screen.blit(text, textRect)
    pygame.display.update()

pygame.init()
screen = pygame.display.set_mode( (640,480) )
pygame.display.set_caption('Python numbers')
screen.fill((159, 182, 205))

font = pygame.font.Font(None, 17)

num = 0
done = False
while not done:
    display( str(num) )
    num += 1

    pygame.event.pump()
    keys = pygame.key.get_pressed()
    if keys[K_ESCAPE]:
        done = True
Tuesday, June 1, 2021
 
JackTheKnife
answered 6 Months ago
74

I would do this by creating separate a thread which calls normal blocking IO functions and pass it a callback function which it would call when it got input. Are you sure you need to do what you said you want to do?

As for outputting information at the same time, what would happen if the user was in the middle of typing some input and you printed something?

Wednesday, June 2, 2021
 
hakre
answered 6 Months ago
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