由于工作中经常用到关于用户自定义时间，来进行后台数据的查询，特意整理了一下工作中常用的到的关于时间列表的一个函数，可以计算出某一年中的具体哪个周的开始和结束日期，某个周的具体日期列表(2015年38周)，自定义时间段的具体日期列表(20150901-20151010)
1、计算当前日期：import datetime
print datetime.datetime.now()
2、计算昨天和明天的日期yesterday = (datetime.datetime.now() - datetime.timedelta(days=1)).strftime("%Y%m%d")
tomorrow = (datetime.datetime.now() + datetime.timedelta(days=1)).strftime("%Y%m%d")
3、计算某一月有多少天import calendar
monthRange = calendar.monthrange(2013,6)
print monthRange
输出：
(5, 30)
输出的是一个元组，第一个元素是上一个月的最后一天为星期几(0-6),星期天为0;第二个元素是这个月的天数。
4、计算周的日期函数。包含某一周开始、结束日期，周的详细日期列表import datetime
def allweeks(week):
"计算一年内所有周的具体日期"
_week = int(week)-1
current = datetime.datetime.now()
start = datetime.date(current.year,1,1)
last_day = datetime.date(current.year,12,31)
isfirst = start.weekday()
last_week = last_day.strftime('%W')
weeks={} #计算出一年中每个周的开始和结束日期。例如：0: [datetime.date(2015, 1, 1), datetime.date(2015, 1, 4)]
date_list_for_week = [] #用于得出具体的某一个周的具体天数列表：例如: 第9周：['20150223', '20150224', '20150225', '20150226', '20150227', '20150228', '20150301']
if isfirst !=0:
end = datetime.timedelta(7-start.weekday()-1)
weeks[0]=[start,start+end]
start += datetime.timedelta(7 - start.weekday())
for i in range(0,int(last_week)):
days = datetime.timedelta(weeks=i)
end = start + days
if i+1 == int(last_week):
weeks[i+1] = [end,last_day]
else:
weeks[i+1] = [end,end + datetime.timedelta(6)]
starttime = ''.join(str(weeks[_week][0]).split('-'))#计算出给出周的开始日期，如20150907
endtime = ''.join(str(weeks[_week][1]).split("-"))#计算出给出周的结束日期，如201509013
delta = datetime.timedelta(days=1)
startdate = datetime.datetime(int(starttime[0:4]),int(starttime[4:6]),int(starttime[6:8]))
if int(starttime[4:6]) == int(endtime[4:6]):
for i in range(int(endtime[6:]) - int(starttime[6:])+1):
days = (startdate +delta*i).strftime('%Y%m%d')
date_list_for_week.append(days)
elif int(starttime[4:6]) != int(endtime[4:6]):
for i in range(7):
days = (startdate +delta*i).strftime('%Y%m%d')
date_list_for_week.append(days)
return date_list_for_week,weeks,starttime,endtime
if __name__ == "__main__":
week =9
print allweeks(week)
5、计算自定义时间的日期函数。(比如计算20150811-20150922之间的日期列表)import datetime
def get_datelist(starttime,endtime):
startdate = datetime.datetime(int(starttime[0:4]),int(starttime[4:6]),int(starttime[6:8]))
#now = datetime.datetime.now()
delta = datetime.timedelta(days=1)
# my_yestoday = startdate + delta
# my_yes_time = my_yestoday.strftime('%Y%m%d')
n = 0
date_list = []
while 1:
if starttime<=endtime:
days = (startdate + delta*n).strftime('%Y%m%d')
n = n+1
date_list.append(days)
if days == endtime:
break
return date_list
print get_yestoday('20150811','20150922')
6、将自定义时间分割成星期来进行取值，不足一星期的按天来取值def startdate_enddate_weeks_list(startdate,enddate):
'''计算startdate---enddate的周所属的周和周包含的日期列表
week_date_start_end {1: ['20181231','20190106'],...}
'''
start_date=datetime.datetime.strptime(str(startdate),'%Y%m%d')
end_date=datetime.datetime.strptime(str(enddate),'%Y%m%d')
_u=datetime.timedelta(days=1)
n=0
week_date=collections.OrderedDict()
date=[]
while 1:
_time=start_date+n*_u
y,w=_time.isocalendar()[:2]
year_week=str(y)+str(w)
if week_date.has_key(year_week):
date.append(_time.strftime('%Y%m%d'))
else:
date=[_time.strftime('%Y%m%d')]
week_date[year_week]=date
n=n+1
if _time==end_date:
break
return week_date
a=startdate_enddate_weeks_list("20151011","20151102")
print a
([('201541', ['20151011']), ('201542', ['20151012', '20151013', '20151014', '20151015', '20151016', '20151017', '20151018']), ('201543', ['20151019', '20151020', '20151021', '20151022', '20151023', '20151024', '20151025']), ('201544', ['20151026', '20151027', '20151028', '20151029', '20151030', '20151031', '20151101']), ('201545', ['20151102'])])
7、计算当前天的前一周的天数。def seven_day_list(year_mon_day,i,n):
'''计算当前天的前七天列表,例如：2015-09-10---------2015-10-10'''
myday = datetime.datetime( int(year_mon_day[0:4]),int(year_mon_day[4:6]),int(year_mon_day[6:8]) )
day_list = []
for i in xrange(i,n):
days = (myday + datetime.timedelta(days=-i)).strftime('%Y-%m-%d')
day_list.append(days)
return day_list[::-1]8、算出某一日期所属当前月的所有日期列表，dates是一个具体日期：例20160307def get_one_mon_all_daylist(dates):
'''得到一个月的具体日期列表：从1号到月末的天列表'''
a_mon_daylist = []
mon_days = calendar.monthrange(int(dates[:4]),int(dates[4:6]))[1]#得到当前月的天数
for i in xrange(1,int(mon_days)+1):
if len(str(i)) == 1:
a_mon_daylist.append(dates[:6]+"0"+str(i))
elif len(str(i)) == 2:
a_mon_daylist.append(dates[:6]+str(i))
return a_mon_daylist
