显示 python sleep 函数的倒计时
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Display a countdown for the python sleep function
提问by user1681664
I am using time.sleep(10) in my program. Can display the countdown in the shell when I run my program?
我在我的程序中使用 time.sleep(10)。当我运行我的程序时，可以在 shell 中显示倒计时吗？
>>>run_my_program()
tasks done, now sleeping for 10 seconds
and then I want it to do 10,9,8,7....
然后我想让它做 10,9,8,7 ....
is this possible?
这可能吗？
采纳答案by aestrivex
you could always do
你总能做到
#do some stuff
print 'tasks done, now sleeping for 10 seconds'
for i in xrange(10,0,-1):
time.sleep(1)
print i
This snippet has the slightly annoying feature that each number gets printed out on a newline. To avoid this, you can
这个片段有一个有点烦人的功能，每个数字都打印在换行符上。为避免这种情况，您可以
import sys
import time
for i in xrange(10,0,-1):
sys.stdout.write(str(i)+' ')
sys.stdout.flush()
time.sleep(1)
回答by Silas Ray
Sure, just write a loop that prints 10 minus the iteration counter, then have it sleep 1 second each iteration and run for 10 iterations. Or, to be even more flexible:
当然，只需编写一个循环，打印 10 减去迭代计数器，然后让它每次迭代休眠 1 秒并运行 10 次迭代。或者，更灵活：
def printer(v):
print v
def countdown_timer(duration, step=1, output_function=printer,
prompt='Waiting {duration} seconds.'):
output_function(prompt.format(duration=duration))
for i in xrange(duration/step):
output_function(duration - step * i)
回答by Saullo G. P. Castro
You can do a countdown function like:
您可以执行倒计时功能，例如：
import sys
import time
def countdown(t, step=1, msg='sleeping'): # in seconds
pad_str = ' ' * len('%d' % step)
for i in range(t, 0, -step):
print '%s for the next %d seconds %s\r' % (msg, i, pad_str),
sys.stdout.flush()
time.sleep(step)
print 'Done %s for %d seconds! %s' % (msg, t, pad_str)
The carriage return \rand the comma ,will keep the print in the same line (avoiding one line for each countdown value)
回车\r和逗号,将使打印保持在同一行（每个倒计时值避免一行）
As the number of seconds decreases, the pad_str will ensure the last line is overwritten with spaces instead of leaving the last character(s) behind as the output shortens.
随着秒数的减少，pad_str 将确保最后一行被空格覆盖，而不是随着输出的缩短而留下最后一个字符。
The final print overwrites the last status message with a done message and increments the output line, so there is evidence of the delay.
最后的打印用完成消息覆盖最后一个状态消息并增加输出行，因此有延迟的证据。
回答by Silas Poulson
Here's one I did:
这是我做的一个：
import time
a = input("How long is the countdown?")
while a != 0:
print a
time.sleep(1)
a = a-1
At the end if you and an else you can put an alarm or whatever.
最后，如果您和其他人可以设置闹钟或其他什么。
回答by jfs
time.sleep()may return earlier if the sleep is interrupted by a signal or later (depends on the scheduling of other processes/threads by OS/the interpreter).
time.sleep()如果睡眠被信号中断或稍后（取决于操作系统/解释器对其他进程/线程的调度），则可能会更早返回。
To improve accuracy over multiple iterations, to avoid drift for large number of iterations, the countdown may be locked with the clock:
为了提高多次迭代的准确性，避免大量迭代的漂移，倒计时可能会被时钟锁定：
#!/usr/bin/env python
import sys
import time
for i in reversed(range(1, 1001)):
time.sleep(1 - time.time() % 1) # sleep until a whole second boundary
sys.stderr.write('\r%4d' % i)
回答by Azur
This is something that I've learned at one of my first python lessons, we played with ["/","-","|","\","|"] but the principle is the same:
这是我在第一次 Python 课程中学到的东西，我们使用 ["/","-","|","\","|"] 但原理是相同的：
import time
for i in reversed(range(0, 10)):
time.sleep(1)
print "%s\r" %i,
回答by Barkles
This is the best way to display a timer in the console for Python 3.x:
这是在 Python 3.x 的控制台中显示计时器的最佳方式：
import time
import sys
for remaining in range(10, 0, -1):
sys.stdout.write("\r")
sys.stdout.write("{:2d} seconds remaining.".format(remaining))
sys.stdout.flush()
time.sleep(1)
sys.stdout.write("\rComplete! \n")
This writes over the previous line on each cycle.
这会在每个循环中覆盖上一行。
