date&time

1.求时间差（按天、按月、按年）

from dateutil.relativedelta import relativedelta
datetime.datetime.today+ relativedelta(days=1)
datetime.datetime.today+ relativedelta(months=1)
datetime.datetime.today+ relativedelta(years=1)

2.时间格式转换成字符串

import time 
from datetime import datetime
time.strftime('%Y%m%d %H:%M:%M')
datetime.now().strftime('%Y%m%d %H:%M:%M')

3.字符串转时间

from datetime import datetime,timedelta
#处理'2018-1-1'
t1 = datetime.strptime('2018-1-1',"%Y-%m-%d")
#处理'23-10-2018'
t2 = datetime.strptime('23-10-2018','%d-%m-%Y')
t3 = t2 + timedelta(days=1))

4.根据年月日生成日期

import datetime
t = datetime.datetime(2018,10,29,10,10,10)