Python 12天的圣诞节

Question

The following will allow me to find out what happens on a day of Christmas, but how would I go about getting it to work like the song - so the 5th day would start with gold rings and work backwards to the pear tree?! Something to do with an ordered data structure like a list?

day = input('What day of Christmas is it? ')

days = {'first':'A Partridge in a Pear Tree','second':'Two Turtle Doves',
'third':'Three French Hens','fourth':'Four Calling Birds','fifth':'Five Golden Rings',
'sixth':'Six Geese a Laying','seventh':'Seven Swans a Swimming','eighth':'Eight Maids a Milking',
'ninth':'Nine Ladies Dancing','tenth':'Ten Lords a Leaping','eleventh':'Eleven Pipers Piping',
'twelfth':'12 Drummers Drumming'}

print('On the',day.lower(),'day of Christmas my true love gave to me:')
print(days[day.lower()])

Thanks

Answer 1

There's no need to use a dictionary when a tuple will do the job. Instead of using the words as indexes, you can use their position in the list as an index.

>>> days = (('first', 'A Partridge in a Pear Tree'),
   ('second', 'Two Turtle Doves'),
   ('third', 'Three French Hens'),
   ('fourth', 'Four Calling Birds'),
   ('fifth', 'Five Golden Rings'),
   ('sixth', 'Six Geese a Laying'),
   ('seventh', 'Seven Swans a Swimming'),
   ('eighth', 'Eight Maids a Milking'),
   ('ninth', 'Nine Ladies Dancing'),
   ('tenth', 'Ten Lords a Leaping'),
   ('eleventh', 'Eleven Pipers Piping'),
   ('twelfth', '12 Drummers Drumming'))
>>> daynum = int(input('What day of Christmas is it? '))
... for i in range(daynum - 1, -1, -1):
...     if i == daynum - 1:
...         print("On the {} day of Christmas my true love gave to me: ".format(days[i][0]))
...     if i == 0 and daynum != 1: # if it's the first day and there isn't only 1 day
...         print("And ", end='')
...     print(days[i][1])
What day of Christmas is it? 4
On the fourth day of Christmas my true love gave to me: 
Four Calling Birds
Three French Hens
Two Turtle Doves
And A Partridge in a Pear Tree

Answer 2

You could organise your data in a list and then iterate on it in reverse order:

sentences = [
    'A Partridge in a Pear Tree',
    'Two Turtle Doves',
    'Three French Hens',
    '...',
]

days = [ 'first', 'second', 'third', 'fourth', '...' ]

day = input('What day of Christmas is it? ')

print("On the {} day of Christmas my true love gave to me:".format(days[day]))

for sentence in list(reversed(sentences))[-day:]:
    print(sentence)

Answer 3

Sorted it with a dictionary and a list!

day = int(input('What day of Christmas is it? (1-12) '))

days_dict = {1:'first',2:'second',3:'third',4:'fourth',5:'fifth',6:'sixth',7:'seventh',8:'eighth',
        9:'ninth',10:'tenth',11:'eleventh',12:'twelfth'}

days_list = ['And a Partridge in a Pear Tree!','Two Turtle Doves','Three French Hens','Four Calling Birds',
         'Five Golden Rings','Six Geese a Laying','Seven Swans a Swimming','Eight Maids a Milking',
         'Nine Ladies Dancing','Ten Lords a Leaping','Eleven Pipers Piping','12 Drummers Drumming']

print('On the',days_dict[day],'day of Christmas my true love gave to me:')

result = days_list[day-1::-1]

if day == 1:
  print('A partridge in a pair tree')
else:
  for item in result:
    print(item)

Answer 4

What's wrong using the key?

days['first']

times = [ 'first', 'second', 'third', 'fourth']
for t in times:
    print("On the {} day of Christmas my true love gave to me:".format(days[t]))

Answer 5

Use an OrderedDict, iterate backwards until you match your key, on that iteration start printing.

day = input('What day of Christmas is it? ')

days = OrderedDict([
   ('first', 'A Partridge in a Pear Tree'),
   ('second', 'Two Turtle Doves'),
   ('third', 'Three French Hens'),
   ('fourth', 'Four Calling Birds'),
   ('fifth', 'Five Golden Rings'),
   ('sixth', 'Six Geese a Laying'),
   ('seventh', 'Seven Swans a Swimming'),
   ('eighth', 'Eight Maids a Milking'),
   ('ninth', 'Nine Ladies Dancing'),
   ('tenth':'Ten Lords a Leaping'),
   ('eleventh', 'Eleven Pipers Piping'),
   ('twelfth', '12 Drummers Drumming')
])

found = False
print('On the {} day of Christmas, my true love gave to me:'.format(day.lower()))
for ordinal_day, gift in reversed(days.items()):
   if ordinal_day == day:
      found = True
   if found:
      print('\t'+gift)

 if not found:
      print ('\tBupkis, input must be "first", "second", etc.')

Alternatively, use an OrderedDict, add the items in reverse order, and iterate forwards through the dictionary.

Answer 6

Just use a list. Ask the day and reverse print the list.

days_of_christmas = (('first', 'A Partridge in a Pear Tree.'), ('second', 'Two Turtle Doves, and'),
           ('third', 'Three French Hens,'), ('fourth', 'Four Calling Birds,'),
           ('fifth', 'Five Golden Rings,'), ('sixth', 'Six Geese a Laying,'),
           ('seventh', 'Seven Swans a Swimming,'), ('eighth', 'Eight Maids a Milking,'),
           ('ninth', 'Nine Ladies Dancing,'), ('tenth', 'Ten Lords a Leaping,'),
           ('eleventh', 'Eleven Pipers Piping,'), ('twelfth', 'Twelve Drummers Drumming,'))

day = int(input('What day of Christmas is it? (1-12) ')) - 1 
print("\nOn the {} day of Christmas my true love sent to me: ".format(days_of_christmas[day][0]))
for gift in range(day, -1, -1):          
    print(days_of_christmas[gift][1])