python – 循环中具有超时的用户输入
作者:互联网
我正在尝试创建一个循环python函数,它执行任务并提示用户进行响应,如果用户在给定时间内没有响应,则序列将重复.
这是基于这个问题的松散基础:How to set time limit on raw_input
该任务由some_function()表示.超时是一个变量,以秒为单位.我有以下代码的两个问题:
>无论用户是否提示,raw_input提示在指定的4秒时间后都不会超时.
>当输入’q’的raw_input时(没有”,因为我知道任何键入的内容会自动输入为字符串),该函数不会退出循环.
`
import thread
import threading
from time import sleep
def raw_input_with_timeout():
prompt = "Hello is it me you're looking for?"
timeout = 4
astring = None
some_function()
timer = threading.Timer(timeout, thread.interrupt_main)
try:
timer.start()
astring = raw_input(prompt)
except KeyboardInterrupt:
pass
timer.cancel()
if astring.lower() != 'q':
raw_input_with_timeout()
else:
print "goodbye"
`
解决方法:
警告:这可以按照要求在* nix和OSX中使用,但绝对不能在Windows中使用.
我使用了this modification的ActiveState配方作为下面代码的基础.它是一个易于使用的对象,可以通过超时读取输入.它使用轮询一次收集一个字符并模拟raw_input()/ input()的行为.
输入超时
注意:显然下面的_getch_nix()方法对OP不起作用,但它在OSX 10.9.5上适用于我.你可能有运气调用_getch_osx(),虽然它似乎只能在32位python中工作,因为Carbon不完全支持64位.
import sys
import time
class TimeoutInput(object):
def __init__(self, poll_period=0.05):
import sys, tty, termios # apparently timing of import is important if using an IDE
self.poll_period = poll_period
def _getch_nix(self):
import sys, tty, termios
from select import select
fd = sys.stdin.fileno()
old_settings = termios.tcgetattr(fd)
try:
tty.setraw(sys.stdin.fileno())
[i, o, e] = select([sys.stdin.fileno()], [], [], self.poll_period)
if i:
ch = sys.stdin.read(1)
else:
ch = ''
finally:
termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
return ch
def _getch_osx(self):
# from same discussion on the original ActiveState recipe:
# http://code.activestate.com/recipes/134892-getch-like-unbuffered-character-reading-from-stdin/#c2
import Carbon
if Carbon.Evt.EventAvail(0x0008)[0] == 0: # 0x0008 is the keyDownMask
return ''
else:
# The event contains the following info:
# (what,msg,when,where,mod)=Carbon.Evt.GetNextEvent(0x0008)[1]
#
# The message (msg) contains the ASCII char which is
# extracted with the 0x000000FF charCodeMask; this
# number is converted to an ASCII character with chr() and
# returned
(what,msg,when,where,mod)=Carbon.Evt.GetNextEvent(0x0008)[1]
return chr(msg & 0x000000FF)
def input(self, prompt=None, timeout=None,
extend_timeout_with_input=True, require_enter_to_confirm=True):
"""timeout: float seconds or None (blocking)"""
prompt = prompt or ''
sys.stdout.write(prompt) # this avoids a couple of problems with printing
sys.stdout.flush() # make sure prompt appears before we start waiting for input
input_chars = []
start_time = time.time()
received_enter = False
while (time.time() - start_time) < timeout:
# keep polling for characters
c = self._getch_osx() # self.poll_period determines spin speed
if c in ('\n', '\r'):
received_enter = True
break
elif c:
input_chars.append(c)
sys.stdout.write(c)
sys.stdout.flush()
if extend_timeout_with_input:
start_time = time.time()
sys.stdout.write('\n') # just for consistency with other "prints"
sys.stdout.flush()
captured_string = ''.join(input_chars)
if require_enter_to_confirm:
return_string = captured_string if received_enter else ''
else:
return_string = captured_string
return return_string
测试一下
# this should work like raw_input() except it will time out
ti = TimeoutInput(poll_period=0.05)
s = ti.input(prompt='wait for timeout:', timeout=5.0,
extend_timeout_with_input=False, require_enter_to_confirm=False)
print(s)
重复输入
这实现了我理解它的初衷.我认为进行递归调用没有任何价值 – 我认为你想要的只是重复输入?如果错误,请纠正我.
ti = TimeoutInput()
prompt = "Hello is it me you're looking for?"
timeout = 4.0
while True:
# some_function()
s = ti.input(prompt, timeout)
if s.lower() == 'q':
print "goodbye"
break
标签:raw-input,python,python-2-7,keyboardinterrupt 来源: https://codeday.me/bug/20191001/1840587.html