转：python 时间日期处理汇集

heberoxx

python 时间日期处理汇集
2011-03-14 16:52

‍#计算精确时间差 　　#----------------------------- # High Resolution Timers t1=time.clock() # Do Stuff Here t2=time.clock() print t2-t1 # 2.27236813618 # Accuracy will depend on platform and OS, # but time.clock() uses the most accurate timer it can time.clock(); time.clock() # 174485.51365466841 # 174485.55702610247 #----------------------------- # Also useful; import timeit code='[x for x in range(10) if x % 2 == 0]' eval(code) # [0, 2, 4, 6, 8] t=timeit.Timer(code) print"10,000 repeats of that code takes:",t.timeit(10000),"seconds" print"1,000,000 repeats of that code takes:",t.timeit(),"seconds" # 10,000 repeats of that code takes: 0.128238644856 seconds # 1,000,000 repeats of that code takes:  12.5396490336 seconds #----------------------------- import timeit code='import random; l = random.sample(xrange(10000000), 1000); l.sort()' t=timeit.Timer(code) print"Create a list of a thousand random numbers. Sort the list. Repeated a thousand times." print"Average Time:",t.timeit(1000) /1000 # Time taken: 5.24391507859 　　 ‍#time , datetime , string 类型互相转换       # string -> time    > time.strptime(publishDate,"%Y-%m-%d %H:%M:%S")    # time -> string    >time.strftime("%y-%m-%d",t) 　　#string ->datetime 　　datetime.strptime(date_string,format)   　　#datetime->string 　　datetime.strftime("%Y-%m-%d %H:%M:%S")   strptime formating 　　Directive 　　Meaning 　　Notes 　　%a 　　Locale’s abbreviated weekday name. 　　　 　　%A 　　Locale’s full weekday name. 　　　 　　%b 　　Locale’s abbreviated month name. 　　　 　　%B 　　Locale’s full month name. 　　　 　　%c 　　Locale’s appropriate date and time representation. 　　　 　　%d 　　Day of the month as a decimal number [01,31]. 　　　 　　%f 　　Microsecond as a decimal number [0,999999], zero-padded on the left 　　-1 　　%H 　　Hour (24-hour clock) as a decimal number [00,23]. 　　　 　　%I 　　Hour (12-hour clock) as a decimal number [01,12]. 　　　 　　%j 　　Day of the year as a decimal number [001,366]. 　　　 　　%m 　　Month as a decimal number [01,12]. 　　　 　　%M 　　Minute as a decimal number [00,59]. 　　　 　　%p 　　Locale’s equivalent of either AM or PM. 　　-2 　　%S 　　Second as a decimal number [00,61]. 　　-3 　　%U 　　Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0. 　　-4 　　%w 　　Weekday as a decimal number [0(Sunday),6]. 　　　 　　%W 　　Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0. 　　-4 　　%x 　　Locale’s appropriate date representation. 　　　 　　%X 　　Locale’s appropriate time representation. 　　　 　　%y 　　Year without century as a decimal number [00,99]. 　　　 　　%Y 　　Year with century as a decimal number. 　　　 　　%z 　　UTC offset in the form +HHMM or -HHMM (empty string if the the object is naive). 　　-5 　　%Z 　　Time zone name (empty string if the object is naive). 　　　 　　%% 　　A literal'%'character. 　　　 　　‍#两日期相减  ‍时间差：    d1 = datetime.datetime(2005, 2, 16)    d2 = datetime.datetime(2004, 12, 31)    print (d1 - d2).days    starttime = datetime.datetime.now()    endtime = datetime.datetime.now()    print (endtime - starttime).seconds    　　‍#计算当前时间向后10天的时间。    #如果是小时 days 换成 hours    d1 = datetime.datetime.now()    d3 = d1 + datetime.timedelta(days =10)    print str(d3)    print d3.ctime()    import datetime, calendar    　　#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 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()