#获取当前的时间
curr_time = datetime.datetime.now()   #2020-06-13 22:06:25.393880 类型：<class 'datetime.datetime'>

   格式化： 

#格式化(使用strftime()将datetime转换成为2020-06-13、2020/06/13等str目标形式)
time_str = curr_time.strftime("%Y-%m-%d")  #2020-06-13  类型：<class 'str'>
time_str = curr_time.strftime("%Y/%m/%d")  #2020/06/13  类型：<class 'str'>

    类型转换： 

#类型转换
# datetime-->str
time_str = datetime.datetime.strftime(curr_time,'%Y-%m-%d %H:%M:%S') #2020-06-13 22:15:29 类型：<class 'str'>#str-->datetime
time_str = '2020-06-13 22:15:29'
curr_time = datetime.datetime.strptime(time_str,'%Y-%m-%d %H:%M:%S') #2020-06-13 22:15:29 类型：<class 'datetime.datetime'>