求两个日期之间间隔的天数，Python实现

 1 def leap_year(y):   #判断是否是闰年
 2     if (y % 4 == 0 and y % 100 != 0) or y % 400 == 0:
 3         return True
 4     else:
 5         return False
 6         
 7 def days_in_month(y, m):    #判断每个月都有几天
 8     if m in [1, 3, 5, 7, 8, 10, 12]:
 9         return 31
10     elif m in [4, 6, 9, 11]:
11         return 30
12     else:
13         if leap_year(y):
14             return 29
15         else:
16             return 28
17             
18 def days_this_year(year):   #判断今年共几天
19     if leap_year(year):
20         return 366
21     else:
22         return 365
23             
24 def days_passed(year, month, day):  #判断今年过了几天
25     m = 1
26     days = 0
27     while m < month:
28         days += days_in_month(year, m)
29         m += 1
30     return days + day
31 
32 def daysBetweenDates(year1, month1, day1, year2, month2, day2):
33     ##
34     # Your code here.
35     ##
36     if year1 == year2:
37         return days_passed(year2, month2, day2) - days_passed(year1, month1, day1)
38     else:
39         sum1 = 0
40         y1 = year1
41         while y1 < year2:
42             sum1 += days_this_year(y1)
43             y1 += 1
44         return sum1-days_passed(year1,month1,day1)+days_passed(year2,month2,day2)

def test():
    test_cases = [((2012,1,1,2012,2,28), 58), 
                  ((2012,1,1,2012,3,1), 60),
                  ((2011,6,30,2012,6,30), 366),
                  ((2011,1,1,2012,8,8), 585 ),
                  ((1900,1,1,1999,12,31), 36523)]
    for (args, answer) in test_cases:
        result = daysBetweenDates(*args)
        if result != answer:
            print "Test with data:", args, "failed"
        else:
            print "Test case passed!"

test()