#coding:utf-8
'''
base on python 2.7
Created on 2012-12-14
@author: yiahomen.com
'''
import datetime
import time
def datetime_toString(dt):
  """把datetime转成字符串"""
  return dt.strftime("%Y-%m-%d")
def string_toDatetime(string):
  """把字符串转成datetime"""
  return datetime.datetime.strptime(string, "%Y-%m-%d")
def string_toTimestamp(strTime):
  """把字符串转成时间戳形式"""
  return time.mktime(string_toDatetime(strTime).timetuple())
def timestamp_toString(stamp):
  """把时间戳转成字符串形式"""
  return time.strftime("%Y-%m-%d-%H", time.localtime(stamp))
def datetime_toTimestamp(dateTime):
  """把datetime类型转外时间戳形式"""
  return time.mktime(dateTime.timetuple())
def substract_DateTime(dateStr1,dateStr2):
  """ 返回两个日期之间的差 """
  d1=string_toDatetime(dateStr1)
  d2=string_toDatetime(dateStr2)
  return d2-d1
def substract_TimeStamp(dateStr1,dateStr2):
  """ 两个日期的 timestamp 差值 """
  ts1= string_toTimestamp(dateStr1)
  ts2= string_toTimestamp(dateStr2)
  return ts1-ts2
def compare_dateTime(dateStr1,dateStr2):
  """两个日期的比较, 当然也可以用timestamep方法比较,都可以实现."""
  date1 = string_toDatetime(dateStr1)
  date2 = string_toDatetime(dateStr2)
  return date1.date()>date2.date()
def dateTime_Add(dateStr,days=0,hours=0,minutes=0):
  """ 指定日期加上 一个时间段，天，小时，或分钟之后的日期 """
  date1= string_toDatetime(dateStr)
  return date1+datetime.timedelta(days=days,hours=hours,minutes=minutes)
if __name__=='__main__':
  print substract_DateTime('2012-12-12','2012-01-01')
  #-346 days, 0:00:00
  print substract_DateTime('2012-12-12','2012-01-01').days
  #-346
  print substract_TimeStamp('2012-12-12','2012-01-01')
  #29894400.0
  print substract_TimeStamp('2012-12-12','2012-01-01')/(24*60*60),'天'
  #346.0 天
  print compare_dateTime('2012-12-12','2012-01-01')
  #True
  print dateTime_Add('2012-12-12',days=10,hours=5,minutes=10)
  #2012-12-22 05:10:00

import calendar, datetime
def increment_month(when):
  days = calendar.monthrange(when.year, when.month)[1]
  return when + datetime.timedelta(days=days)
now = datetime.datetime.now()
print 'It is now %s' % now
print 'In a month, it will be %s' % increment_month(now)