输出进度条

import time
for i in range(0,101,2):
    time.sleep(0.2)
    char_num=i//2
    per_str=('\r%s%%:%s\n' %(i,'*'* char_num) if i==100 else '\r%s%%:%s' %(i,'*'*char_num))#三元判断
    print(per_str,end='',flush=True)