date、datetime、string的相互转换

import datetime
import time

string转datetime
            str = '2012-11-19'
            date_time = datetime.datetime.strptime(str,'%Y-%m-%d')
            date_time
datetime.datetime(,,,,)

datetime转string
            date_time.strftime('%Y-%m-%d')
'2012-11-19'

datetime转时间戳
            time_time = time.mktime(date_time.timetuple())
            time_time
1353254400.0

时间戳转string
            time.strftime('%Y-%m-%d',time.localtime(time_time))
'2012-11-19'

date转datetime
            date = datetime.date.today()
            date
            datetime.date(,,)
            datetime.datetime.strptime(str(date),'%Y-%m-%d') #将date转换为str，在由str转换为datetime
            datetime.datetime(,,,,)