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分享python有办法暂时关闭输入吗
我的一段程序需要输入密码，多次错误就会延时在次输入。延时的时候我使用了time.sleep(sec) 这样的方法，但是发现在这个时候还是可以按键盘输入的 只是不能被显示罢了，在延时之后，他就会被再次读入，当然密码是输入是错误的，所以他又会继续延时。我考虑这是一个bug,如果输入个一百次一千次，其中有一次恰好输入正确了。第二天再来看程序，发现已经进去了。所以想问问有没有什么方法可以把，输入定向到其他地方，或者直接丢弃
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wy_ei 2014-10-18
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but it only works on Windows system, does it? You would think that python could offer cross-platform capability here...
take a look at python/Modules/posixmodule.c and didn't find anything. It appears python simply passes it through to whatever implementation on the OS level to handle the arguments sent to the C STD call "system"...
Don't know why pause under windows could clean up the console input queue either...
But I guess he doesn't care...[/quote]
thanks for your patient answer.you let me know when we do program we should consider the cross-platform capability .I think I should take some time to learn another OS.
小笨和漂向北方 2014-10-11
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but it only works on Windows system, does it? You would think that python could offer cross-platform capability here...
take a look at python/Modules/posixmodule.c and didn't find anything. It appears python simply passes it through to whatever implementation on the OS level to handle the arguments sent to the C STD call "system"...
Don't know why pause under windows could clean up the console input queue either...
But I guess he doesn't care...
wy_ei 2014-10-11
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确实是这样，可以用他来解决问题。多谢。
wy_ei 2014-10-11
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当我多次输错以后，显示让我等待，但是我依旧多次输入，时间到了以后，按以前的情况会再次被raw_input读入，这下不会了。
代码中我添加了os.system('pause')在输入的前面
while right!=1:
os.system('pause')
pswd1=raw_input("please enter password:")wy_ei 2014-10-11
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这个问题貌似很有意思，下面是我的代码，帮忙看看
right=0
while right!=1:
pswd1=raw_input("please enter password:")
pswd=self.getPasswd()
if pswd1==pswd:
right=1
self.setWrongTimes(0)
else:
self.setWrongTime(time.time()) #record the time when wrong input occur
self.wrongTimes+=1
print "password wrong!"
self.setWrongTimes(self.wrongTimes) # set wrongs times
self.WiatTime() # wiat def WiatTime(self): #according the password input wrong times set a wait time,at this time you can't enter password
times=self.getWrongTimes() #wrong times
wrongTime =self.getWrongTime() #the time last wrong input accour
if times <= 3:
pass
if times >3:
currentTime=long(time.time())
waitTime=currentTime-wrongTime
if waitTime>times*times:
pass
else:
timeYouShouldWait=times*times-(currentTime-wrongTime)
print "you should wait for some sec: ",
for i in range(timeYouShouldWait):
time.sleep(1)
theTimeLave=timeYouShouldWait-i
if theTimeLave<10:
print "\b\b\b",str(theTimeLave),
elif theTimeLave<100:
print "\b\b\b\b",str(theTimeLave),
elif theTimeLave<1000:
print "\b\b\b\b\b\b",str(theTimeLave),
print 
angel_su 2014-10-10
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貌似os.system('pause')一下可以清除先前的输入...
The_Third_Wave 2014-10-10
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mark
小笨和漂向北方 2014-10-10
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Then, if python exactly relies on C stdin, there is no function available to flush stdin buffer. However, you could consume those unnecessary characters by:
While True:
c=sys.stdin.read(1)
if s=='\n' or c==None:
break
See C FAQ 12.26b[/quote]
问题是消耗光已有的输入后,read不会返回None, 而是会被阻塞. 另外, c=='\n'就推出循环的话, 只能消耗掉一行.[/quote]
please discard all my previous comments here. I totally misunderstood the question and offered wrong direction and my understanding to the stdin/stdout buffer was also wrong which is actually not related to this question at all...
I don't know windows, but for unix/linux, we are actually talking about tty device here. So the right interpretation of this question is: how could we pause tty input or flush tty input queue?
man 3 tcflush
#include <unistd.h>
#include <stdio.h>
#include <termios.h>
void main(void)
{
char c;
sleep(5);
printf("wake up\n");
tcflush(0,TCIFLUSH);
while((c=getchar())!='\n'&&c!=EOF)putchar(c);
return;
}
import time
import subprocess
import sys
from termios import tcflush, TCIOFLUSH
alarm1 = int(raw_input("How many minutes (alarm1)? "))
while (1):
time.sleep(60*alarm1)
print "Alarm1"
sys.stdout.flush();
tcflush(sys.stdin, TCIOFLUSH)
doit = raw_input("Continue (Y/N)?[Y]: ")
print "Input",doit
if doit == 'N' or doit=='n':
print "Exiting....."
break
小笨和漂向北方 2014-10-09
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Then, if python exactly relies on C stdin, there is no function available to flush stdin buffer. However, you could consume those unnecessary characters by:
While True:
c=sys.stdin.read(1)
if s=='\n' or c==None:
break
See C FAQ 12.26b[/quote]
问题是消耗光已有的输入后,read不会返回None, 而是会被阻塞. 另外, c=='\n'就推出循环的话, 只能消耗掉一行.[/quote]
that's interesting, if python read from stdin can't catch EOF...
As for multiple lines situation, is stdin line buffered? So, if we redirect it to /dev/null before we execute the above clean up buffer routine, we should expect to deal with only one line in the buffer...
jeky_zhang2013 2014-10-09
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设置标志符，当多次输错后，不进行认证，并清空输入缓存
panghuhu250 2014-10-09
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Then, if python exactly relies on C stdin, there is no function available to flush stdin buffer. However, you could consume those unnecessary characters by:
While True:
c=sys.stdin.read(1)
if s=='\n' or c==None:
break
See C FAQ 12.26b[/quote]
问题是消耗光已有的输入后,read不会返回None, 而是会被阻塞. 另外, c=='\n'就推出循环的话, 只能消耗掉一行.
惟愿莲心不染尘 2014-10-09
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如果每次都使用新的缓冲区呢？
小笨和漂向北方 2014-10-09
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Then, if python exactly relies on C stdin, there is no function available to flush stdin buffer. However, you could consume those unnecessary characters by:
While True:
c=sys.stdin.read(1)
if s=='\n' or c==None:
break
See C FAQ 12.26b
panghuhu250 2014-10-09
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这个问题不容易解决, 可以参考这个:http://stackoverflow.com/questions/2520893/how-to-flush-the-input-stream-in-python
改变stdin的办法是不行的. stdin指向os.devnull后, keyboard的输入依然输入到oldf, 等到stdin转回oldf时, 依然会有残存的输入存在.
从应用的角度看, 几次密码不对, 程序直接退出也是一个办法.
惟愿莲心不染尘 2014-10-09
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1L正解，
每次接受输入判断失败后，都先重定向到一个新的缓冲区，
等到sleep结束要再次接受输入时再重定向回原缓冲区
小笨和漂向北方 2014-10-09
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if you'd like to redirect stdin, here it is:
import os
oldf=sys.stdin
f=open(os.devnull, 'r')
sys.stdin=f
