實現輸入某年某月某日計算出這一天是該年第幾天的方法
方法一：笨辦法

 1 list_day = [0,31,28,31,30,31,30,31,31,30,31,30,31]
 2 year = int(input(‘請輸入年‘))
 3 month = int(input(‘請輸入月‘))
 4 day = int(input(‘請輸入日‘))
 5 month_day = 0
 6 if 0<month<=12:
 7     if year % 400 == 0 or ((year % 4 ==0) and (year % 100 != 0)):
 8         print(‘{}是閏年
 
‘.format(year))
 9         list_day[1] = 29
10         for i in range(month-1):
11             month_day += list_day[i]
12         if day <= list_day[month]:
13             count_day = month_day + day
14             print(count_day)
15         else:
16             print(‘day error‘)
17 
18
 
     else:
19         for i in range(month):
20             month_day += list_day[i]
21         if day <= list_day[month]:
22             count_day = month_day + day
23             print(count_day)
24         else:
25             print(‘day error‘)
26 else:
27     print(‘month error‘)

方法二：簡化方法一

 1 list_day = [0,31,28,31,30,31,30,31,31,30,31,30,31]
 2 year = int(input(‘請輸入年‘))
 3 month = int(input(‘請輸入月‘))
 4 day = int(input(‘請輸入日‘))
 5 if 0< month <=12:
 6     sum = list_day[month-1]
 7 else:
 8     print(‘data error‘)
 9 sum += day
10 
11 leap = 0 #
12 if year % 400 == 0 or ((year % 4 ==0) and (year % 100 != 0)):
13     leap = 1
14 if leap == 1 and month > 2:
15     sum += 1
16 print(sum)

方法三：使用模塊time和datetime

1 import datetime
2 import time
3 def function2(year, month, day): # 直接使用Python內置模塊datetime的格式轉換功能得到結果
4     date = datetime.date(year, month, day)
5     return date.strftime(‘%j‘)
6 print(function2(2018,12,3))

練習四：日期計算（輸入某年某月某日計算出這一天是該年第幾天的方法）