子流程Python的常见做法

Question

不幸的是我只限于Python 2.4并希望在我的脚本执行时运行ascii动画（即一个旋转的圆圈）我只是想知道做这样的事情和任何/所有的常见方法或实践是什么与解决方案相关的资源，示例脚本会很棒!!我一直在使用os.sytem（'命令'）并希望摆脱这种习惯。

谢谢！

Answer 1

一种可能的方法是使用回车符“\ _”将光标返回到行的开头，这样就可以覆盖以前写入的字符。这允许您创建动画，只要它适合当前行。例如：

import time

def do_a_little_work():
    time.sleep(0.1)

print "about to do work..."

icons = ["-", "/", "|", "\\"]
icon_idx = 0

while True:
    do_a_little_work()
    #todo: check if work is done, and break out of the loop.
    print "\r" + icons[icon_idx],
    icon_idx = (icon_idx+1)%len(icons)

print "\rdone."

结果：

about to do work...
-

哪个成为

about to do work...
/

哪个成为

about to do work...
|

哪个成为

about to do work...
\

等等......最后成为

about to do work...
done.

---

您可以使用threading与常规代码同时运行动画。

from threading import Thread
import time

def do_the_work():
    #execute your script here

work_thread = Thread(target=do_the_work)
print "Working..."
work_thread.start()

icons = ["-", "/", "|", "\\"]
icon_idx = 0
while work_thread.is_alive():
    time.sleep(0.1)
    print "\r" + icons[icon_idx],
    icon_idx = (icon_idx+1)%len(icons)
print "\rdone"