从sys.stdin获取输入，非阻塞 [英] Taking input from sys.stdin, non-blocking

问题描述

我正在为一个机器人比赛，该机器人通过sys.stdin接收其输入，并使用Python的print()进行输出.我有以下内容:

import sys

def main():
    while True:
        line = sys.stdin.readline()
        parts = line.split()
        if len(parts) > 0:
            # do stuff

问题是输入是通过流输入的，并且使用上面的命令使我无法打印任何内容，直到关闭流.我该怎么做才能使这项工作成功?

解决方案

通过关闭屏蔽功能，您一次只能读取一个字符.因此，没有办法让readline()在非阻塞上下文中工作.我假设您只是想阅读按键来控制机器人.

我在Linux上使用select.select()并没有运气，并通过调整termios设置创建了一种方法.因此，这是特定于Linux的，但对我有用:

old_settings=None

def init_anykey():
   global old_settings
   old_settings = termios.tcgetattr(sys.stdin)
   new_settings = termios.tcgetattr(sys.stdin)
   new_settings[3] = new_settings[3] & ~(termios.ECHO | termios.ICANON) # lflags
   new_settings[6][termios.VMIN] = 0  # cc
   new_settings[6][termios.VTIME] = 0 # cc
   termios.tcsetattr(sys.stdin, termios.TCSADRAIN, new_settings)

@atexit.register
def term_anykey():
   global old_settings
   if old_settings:
      termios.tcsetattr(sys.stdin, termios.TCSADRAIN, old_settings)

def anykey():
   ch_set = []
   ch = os.read(sys.stdin.fileno(), 1)
   while ch != None and len(ch) > 0:
      ch_set.append( ord(ch[0]) )
      ch = os.read(sys.stdin.fileno(), 1)
   return ch_set;

init_anykey()
while True:
   key = anykey()
   if key != None:
      print key
   else:
      time.sleep(0.1)

此处提供了更好的Windows或跨平台答案: Python非阻塞控制台输入

I'm working on a bot for a competition that receives its input through sys.stdin and uses Python's print() for output. I have the following:

import sys

def main():
    while True:
        line = sys.stdin.readline()
        parts = line.split()
        if len(parts) > 0:
            # do stuff

The problem is that the input comes in through a stream and using the above, blocks me from printing anything back until the stream is closed. What can I do to make this work?

解决方案

By turning blocking off you can only read a character at a time. So, there is no way to get readline() to work in a non-blocking context. I assume you just want to read key presses to control the robot.

I have had no luck using select.select() on Linux and created a way with tweaking termios settings. So, this is Linux specific but works for me:

old_settings=None

def init_anykey():
   global old_settings
   old_settings = termios.tcgetattr(sys.stdin)
   new_settings = termios.tcgetattr(sys.stdin)
   new_settings[3] = new_settings[3] & ~(termios.ECHO | termios.ICANON) # lflags
   new_settings[6][termios.VMIN] = 0  # cc
   new_settings[6][termios.VTIME] = 0 # cc
   termios.tcsetattr(sys.stdin, termios.TCSADRAIN, new_settings)

@atexit.register
def term_anykey():
   global old_settings
   if old_settings:
      termios.tcsetattr(sys.stdin, termios.TCSADRAIN, old_settings)

def anykey():
   ch_set = []
   ch = os.read(sys.stdin.fileno(), 1)
   while ch != None and len(ch) > 0:
      ch_set.append( ord(ch[0]) )
      ch = os.read(sys.stdin.fileno(), 1)
   return ch_set;

init_anykey()
while True:
   key = anykey()
   if key != None:
      print key
   else:
      time.sleep(0.1)

A better Windows or cross-platform answer is here: Python nonblocking console input

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