原则, 以datetime为中心, 起点或中转, 转化为目标对象, 涵盖了大多数业务场景中需要的日期转换处理

步骤:

1. 掌握几种对象及其关系

2. 了解每类对象的基本操作方法

3. 通过转化关系转化

涉及对象

1. datetime

>>> import datetime

>>> now = datetime.datetime.now()

>>> now

datetime.datetime(2015, 1, 12, 23, 9, 12, 946118)

>>> type(now)

2. timestamp

>>> import time

>>> time.time()

1421075455.568243

3. time tuple

>>> import time

>>> time.localtime()

time.struct_time(tm_year=2015, tm_mon=1, tm_mday=12, tm_hour=23, tm_min=10, tm_sec=30, tm_wday=0, tm_yday=12, tm_isdst=0)

4. string

>>> import datetime

>>> datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")

'2015-01-12 23:13:08'

5. date

>>> import datetime

>>> datetime.datetime.now().date()

datetime.date(2015, 1, 12)

datetime基本操作

1. 获取当前datetime

>>> import datetime

>>> datetime.datetime.now()

datetime.datetime(2015, 1, 12, 23, 26, 24, 475680)

2. 获取当天date

>>> datetime.date.today()

datetime.date(2015, 1, 12)

3. 获取明天/前N天

明天

>>> datetime.date.today() + datetime.timedelta(days=1)

datetime.date(2015, 1, 13)

三天前

>>> datetime.datetime.now()

datetime.datetime(2015, 1, 12, 23, 38, 55, 492226)

>>> datetime.datetime.now() - datetime.timedelta(days=3)

datetime.datetime(2015, 1, 9, 23, 38, 57, 59363)

4. 获取当天开始和结束时间(00:00:00 23:59:59)

>>> datetime.datetime.combine(datetime.date.today(), datetime.time.min)

datetime.datetime(2015, 1, 12, 0, 0)

>>> datetime.datetime.combine(datetime.date.today(), datetime.time.max)

datetime.datetime(2015, 1, 12, 23, 59, 59, 999999)

5. 获取两个datetime的时间差

>>> (datetime.datetime(2015,1,13,12,0,0) - datetime.datetime.now()).total_seconds()

44747.768075

6. 获取本周/本月/上月最后一天

本周

>>> today = datetime.date.today()

>>> today

datetime.date(2015, 1, 12)

>>> sunday = today + datetime.timedelta(6 - today.weekday())

>>> sunday

datetime.date(2015, 1, 18)

本月

>>> import calendar

>>> today = datetime.date.today()

>>> _, last_day_num = calendar.monthrange(today.year, today.month)

>>> last_day = datetime.date(today.year, today.month, last_day_num)

>>> last_day

datetime.date(2015, 1, 31)

获取上个月的最后一天(可能跨年)

>>> import datetime

>>> today = datetime.date.today()

>>> first = datetime.date(day=1, month=today.month, year=today.year)

>>> lastMonth = first - datetime.timedelta(days=1)

关系转换

几个关系之间的转化

Datetime Object / String / timestamp / time tuple

关系转换例子

datetime <=> string

datetime -> string

>>> import datetime

>>> datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")

'2015-01-12 23:13:08'

string -> datetime

>>> import datetime

>>> datetime.datetime.strptime("2014-12-31 18:20:10", "%Y-%m-%d %H:%M:%S")

datetime.datetime(2014, 12, 31, 18, 20, 10)

datetime <=> timetuple

datetime -> timetuple

>>> import datetime

>>> datetime.datetime.now().timetuple()

time.struct_time(tm_year=2015, tm_mon=1, tm_mday=12, tm_hour=23, tm_min=17, tm_sec=59, tm_wday=0, tm_yday=12, tm_isdst=-1)

timetuple -> datetime

timetuple => timestamp => datetime [看后面datetime<=>timestamp]

datetime <=> date

datetime -> date

>>> import datetime

>>> datetime.datetime.now().date()

datetime.date(2015, 1, 12)

date -> datetime

>>> datetime.date.today()

datetime.date(2015, 1, 12)

>>> today = datetime.date.today()

>>> datetime.datetime.combine(today, datetime.time())

datetime.datetime(2015, 1, 12, 0, 0)

>>> datetime.datetime.combine(today, datetime.time.min)

datetime.datetime(2015, 1, 12, 0, 0)

datetime <=> timestamp

datetime -> timestamp

>>> now = datetime.datetime.now()

>>> timestamp = time.mktime(now.timetuple())

>>> timestamp

1421077403.0

timestamp -> datetime

>>> datetime.datetime.fromtimestamp(1421077403.0)

datetime.datetime(2015, 1, 12, 23, 43, 23)