import time

time.sleep(1)	暂停1s
time.ctime()	打印当前时间（星期、月、日、时、年）Wed Mar  6 20:42:40 2019
time.gmtime()	time.struct_time(tm_year=2019, tm_mon=3, tm_mday=6, tm_hour=12, tm_min=44, tm_sec=21, tm_wday=2, tm_yday=65, tm_isdst=0)
time.strftime("%Y-%m-%d %H %M %S",t)	格式化输出：2019-03-06 12 49 41
time.perf_counter()	返回一个cpu精确计时时间

t=time.gmtime()
print(time.strftime("%Y-%m-%d %H %M %S",t))

动态刷新 

import turtle,time
scale=100
print("执行开始！\n")
start=time.perf_counter()
for i in range(101):
    a='*'*i
    b='-'*(scale-i)
    percent=int((i/scale)*100)
    end=time.perf_counter()
    times=end-start
    print('\r{p}%:|{a}>>{b}|{t:.02f}s'.format(p=percent,a=a,b=b,t=times),end='')
    time.sleep(0.1)
print("\n执行结束！")

import turtle,time
for i in range(101):
    print('\r{a}%'.format(a=i),end='')
    time.sleep(0.1)