问题
I'm attempting to make a countdown timer starting from 60 seconds. My only problem is that when I run the function, the program prints the code like so:
60
59
58
... etc
How would I go about replacing the 60 from that first line and put the 59 in it's place without printing 60 lines?
Here's my code:
from __future__ import division
import sys, time
def countdown():
seconds = 60
while seconds >= 0:
print seconds
sys.stdout.flush()
time.sleep(1)
seconds -= 1
回答1:
Print an empty line at the beginning of your countdown function. This will create the line needed for \r to work. Now, replace the print seconds part with
sys.stdout.write('\r \r')
sys.stdout.write(str(seconds))
The first line clears the previous, empty line printed at the beginning of the function. The second one outputs the seconds.
The code:
def countdown():
seconds = 60
print ''
while seconds >= 0:
sys.stdout.write('\r \r')
sys.stdout.write(str(seconds))
sys.stdout.flush()
time.sleep(1)
seconds -= 1
来源：https://stackoverflow.com/questions/25752932/how-to-replace-string-from-previous-line-using-r-python