为什么这不起作用？第一个 if 语句有问题

Question

def YearType(year):
leapyear = False
year = int(year)
if  year MOD 4 == 0 or year MOD 400 == 0:
leapyear = True
elif (year MOD 100 == 0):
leapyear = False
elif leapyear == True:
print("wow this year is a leap year!")
else:
print("this isnt a leap year :(")

print YearType(2000)

Answer 1

这里有几个问题:

1. 算法:1900 MOD 4 == 0，但1900是不是闰年
语法:Python使用%而不是MOD
2. 逻辑:elif leapyear == True:应该是if leapyear == True:

代码:

# Business Logics
if  year % 400 == 0:    # 1600, 2000, 2400 are leap years
leapyear = True
elif (year % 100 == 0): # 1800, 1900, 2100 are not leap years
leapyear = False
elif (year % 4 == 0):   # 1996, 2004, 2008, 2012, 2020 are leap years
leapyear = True 
else:
leapyear = False    # 2018, 2019, 2021 are not leap years
# UI
if leapyear:
print("wow this year is a leap year!")
else:
print("this isnt a leap year :(")

编辑:如果你想实现一个功能，我建议把它分成两部分:业务逻辑和UI:

def IsLeapYear(year):
if  year % 400 == 0:
return True
elif (year % 100 == 0):
return False
elif (year % 4 == 0):
return True
else:
return False
def YearType(year):
if (IsLeapYear(year)):
print("wow this year is a leap year!")
else:
print("this isnt a leap year :(")
print(YearType(2000))