Python常用的日期时间处理方法示例

#-*- coding: utf-8 -*-
import datetime


#给定日期向后n天的日期
def dateadd_day(days):
  d1 = datetime.datetime.now()
  d3 = d1 + datetime.timedelta(days)
  return d3


#昨天
def getyesterday():
  today = datetime.date.today()
  oneday = datetime.timedelta(days=1)
  yesterday = today - oneday
  return yesterday


#今天
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 getdaysbefore(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
    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2015-02-02
def datetostr(date):
  return str(date)[0:10]


#时间转换成字符串,格式为2015-02-02
def datetostr_secod(date):
  return str(date)[0:19]


#两个日期相隔多少天，例：2015-2-04和2015-3-1
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


#两个日期之间相差的秒
def datediff_seconds(begindate, enddate):
  format = "%y-%m-%d %h:%m:%s"
  if " " not in begindate or ':' not in begindate:
    bformat = "%y-%m-%d"
  else:
    bformat = format
  if " " not in enddate or ':' not in enddate:
    eformat = "%y-%m-%d"
  else:
    eformat = format
  starttime = strtodatetime(begindate, bformat)
  endtime = strtodatetime(enddate, eformat)
  ret = endtime - starttime
  return ret.days * 86400 + ret.seconds


#获取两个时间段的所有时间,返回list
def getdays(begindate, enddate):
  format = "%y-%m-%d"
  begin = strtodatetime(begindate, format)
  oneday = datetime.timedelta(days=1)
  num = datediff(begindate, enddate) + 1
  li = []
  for i in range(0, num):
    li.append(datetostr(begin))
    begin = begin + oneday
  return li


#获取当前年份 是一个字符串
def getyear(date=datetime.date.today()):
  return str(date)[0:4]


#获取当前月份 是一个字符串
def getmonth(date=datetime.date.today()):
  return str(date)[5:7]


#获取当前天 是一个字符串
def getday(date=datetime.date.today()):
  return str(date)[8:10]


#获取当前小时 是一个字符串
def gethour(date=datetime.datetime.now()):
  return str(date)[11:13]


#获取当前分钟 是一个字符串
def getminute(date=datetime.datetime.now()):
  return str(date)[14:16]


#获取当前秒 是一个字符串
def getsecond(date=datetime.datetime.now()):
  return str(date)[17:19]


def getnow():
  return datetime.datetime.now()


print dateadd_day(10)
#2015-02-14 16:41:13.275000

print getyesterday()
#2015-02-03

print gettoday()
#2015-02-04

print getdaysbefore(3)
#['2015-02-03', '2015-02-02', '2015-02-01']

print datediff('2015-2-01', '2015-10-05')
#246

print datediff_seconds('2015-02-04', '2015-02-05')
#86400

print datediff_seconds('2015-02-04 22:00:00', '2015-02-05')
#7200

print getdays('2015-2-03', '2015-2-05')
#['2015-02-03', '2015-02-04', '2015-02-05']

print datetostr_secod(getnow())
#2015-02-04 16:46:47

print str(getyear(dateadd_day(-50))) + '-'\
  + getmonth() + '-'\
  + getday() + ' '\
  + gethour() + ':'\
  + getminute() + ':'\
  + getsecond()
#2014-02-04 16:59:04

print getnow()
#2015-02-04 16:46:47.454000