问题描述
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我想遍历给定开始时间以来的几个月,并打印第一天和最后一天。我可以手动跟踪它是哪个月份和年份,并使用calendar.monthrange(year,month)来获取天数...但这是最好的方法吗?
from datetime import date
start_date = date(2010,8,1)
end_date = date.today()
# I want to loop through each month and print the first and last day of the month
# 2010,1 to 2010,31
# 2010,9,30
# ....
# 2011,3,1 to 2011,31
# 2011,4,1,to 2011,12 (ends early because it is today)
解决方法
要查找一个月的最后一天,可以使用first_of_next_month-datetime.timedelta(1)。例如:
def enumerate_month_dates(start_date,end_date):
current = start_date
while current <= end_date:
if current.month >= 12:
next = datetime.date(current.year + 1,1,1)
else:
next = datetime.date(current.year,current.month + 1,1)
last = min(next - datetime.timedelta(1),end_date)
yield current,last
current = next
,dateutil模块确实支持此类操作,请参见:http://niemeyer.net/python-dateutil#head-470fa22b2db72000d7abe698a5783a46b0731b57
,从开始日期的第一天开始
计算该月的天数并获得下个月的开始
打印开始日期和(下个月的开始-1天)
这有效:
#!/usr/bin/python
from datetime import date,timedelta
import calendar
start_date = date(2001,8,1)
end_date = date.today()
while True:
if start_date > end_date:
break
days_in_month = calendar.monthrange(start_date.year,start_date.month)[1] # Calculate days in month for start_date
new_ts = calendar.timegm(start_date.timetuple()) + (days_in_month * 24 * 60 * 60) # Get timestamp for start of next month
new_start_date = date(1,1).fromtimestamp(new_ts) # Convert timestamp to date object
print start_date,new_start_date - timedelta(1)
start_date = new_start_date
,好吧,在公历中,每个月的第一天都编号为1,最后一天是下个月的第一天减去一。因此,以最简单的形式:
d = datetime.date(2010,m,1)
print d,datetime.date(2010,m + 1,1) - datetime.timedelta(days=1)
(这在12月不起作用,因为date()的month参数必须在1..12中)