[转]python时间函数

#-*-coding:utf-8-*-   
import datetime, calendar   
  
def getYesterday():   
    today=datetime.date.today()   
    oneday=datetime.timedelta(days=1)   
    yesterday=today-oneday   
   return yesterday   
      
def getToday():   
    return datetime.date.today()     
  
#获取给定参数的前几天的日期，返回一个list   
def getDaysByNum(num):   
     today=datetime.date.today()   
     oneday=datetime.timedelta(days=1)       
     li=[]        
    for i in range(0,num):   
        #今天减一天，一天一天减   
         today=today-oneday   
        #把日期转换成字符串   
        #result=datetostr(today)   
         li.append(datetostr(today))   
    return li   
  
#将字符串转换成datetime类型   
def strtodatetime(datestr,format):       
    return datetime.datetime.strptime(datestr,format)   
  
#时间转换成字符串,格式为2008-08-02   
def datetostr(date):     
    return    str(date)[0:10]   
  
#两个日期相隔多少天，例：2008-10-03和2008-10-01是相隔两天   
def datediff(beginDate,endDate):   
     format="%Y-%m-%d";   
     bd=strtodatetime(beginDate,format)   
     ed=strtodatetime(endDate,format)       
     oneday=datetime.timedelta(days=1)   
     count=0  
    while bd!=ed:   
         ed=ed-oneday   
         count+=1  
    return count   
  
#获取两个时间段的所有时间,返回list   
def getDays(beginDate,endDate):   
     format="%Y-%m-%d";   
     bd=strtodatetime(beginDate,format)   
     ed=strtodatetime(endDate,format)   
     oneday=datetime.timedelta(days=1)   
     num=datediff(beginDate,endDate)+1   
     li=[]   
    for i in range(0,num):   
         li.append(datetostr(ed))   
         ed=ed-oneday   
    return li   
  
#获取当前年份 是一个字符串   
def getYear():   
    return str(datetime.date.today())[0:4]   
  
#获取当前月份 是一个字符串   
def getMonth():   
    return str(datetime.date.today())[5:7]   
  
#获取当前天 是一个字符串   
def getDay():   
    return str(datetime.date.today())[8:10]      
def getNow():   
    return datetime.datetime.now()   
  
       
print getToday()   
print getYesterday()   
print getDaysByNum(3)   
print getDays('2008-10-01','2008-10-05')   
print '2008-10-04 00:00:00'[0:10]   
  
print str(getYear())+getMonth()+getDay()   
print getNow()   

 转自:http://hi.baidu.com/bbsing/blog/item/d96e0bd5f2e647cf50da4b4a.html