#! /usr/bin/python
# coding=utf-8

from datetime import datetime,timedelta

"""
timedelta代表两个datetime之间的时间差
"""
now = datetime.now()
past = past = datetime(2010,11,12,13,14,15,16)

timespan = now - past
#这会得到一个负数
past - now
attrs = [
("days","日"),( ‘seconds‘,"秒"),( ‘microseconds‘,"毫秒")
#(‘min‘,"最小"),( ‘max‘,"最大"),
]
for k,v in attrs:
    "timespan.%s = %s #%s" % (k,getattr(timespan, k),v)

"""
总共相差的秒数
"""
timespan.total_seconds()

"""
实例化一个timespan
请注意它的参数顺序
timedelta([days[, seconds[, microseconds[, milliseconds[, minutes[, hours[, weeks]]]]]]])
"""
timespan = timedelta(days=1)
now - timespan #返回的是datetime型
now + timespan

timespan * 2 #还可以乘哦。代表二倍
timespan / 13

#增加一个月
from calendar import monthrange
now + timedelta(days=monthrange(start.year,start.month)[1])

Python代码  

1. # -*- encoding=UTF-8 -*-  
2. import datetime  
3. def timebefore(d):  
4.      chunks = (  
5.                        (60 * 60 * 24 * 365, u‘年‘),  
6.                        (60 * 60 * 24 * 30, u‘月‘),  
7.                        (60 * 60 * 24 * 7, u‘周‘),  
8.                        (60 * 60 * 24, u‘天‘),  
9.                        (60 * 60, u‘小时‘),  
10.                        (60, u‘分钟‘),  
11.      )  
12.      #如果不是datetime类型转换后与datetime比较  
13.     if not isinstance(d, datetime.datetime):  
14.            d = datetime.datetime(d.year,d.month,d.day)  
15.     now = datetime.datetime.now()  
16.     delta = now - d  
17.     #忽略毫秒  
18.     before = delta.days * 24 * 60 * 60 + delta.seconds  #python2.7直接调用 delta.total_seconds()  
19.     #刚刚过去的1分钟  
20.     if before <= 60:  
21.            return u‘刚刚‘  
22.     for seconds,unit in chunks:  
23.            count = before // seconds  
24.            if count != 0:  
25.                  break  
26.     return unicode(count)+unit+u"前"  

Python代码  

1. #!/usr/bin/env python  
2. # -*- coding:utf-8 -*-  
3.   
4. from datetime import datetime,timedelta  
5.   
6. now = datetime.now()  
7.   
8. yestoday = now - timedelta(days=1)  
9. tommorow = now + timedelta(days=1)  
10.   
11. next_year = now + timedelta(days = 365)