Nested loops.
I looped through a
range
of numbers rather than a list of strings
because numeric comparison
(day == 1)
is faster than string comparison
(day == "first").
“Colly” means “black as coal”; it’s a word we don’t have in American English.
"""
Output the lyrics to "The Twelve Days of Christmas."
"""
import sys
ordinals = [ #a list of 13 strings
None, #Let "first" have index 1.
"first",
"second",
"third",
"fourth",
"fifth",
"sixth",
"seventh",
"eighth",
"ninth",
"tenth",
"eleventh",
"twelfth"
]
gifts = [
None, #Let "partridge in a pear tree." have index 1.
"partridge in a pear tree.", #must be prefixed with "A " or "And a ".
"Two turtledoves",
"Three French hens",
"Four colly 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",
"Twelve drummers drumming"
]
for day in range(1, len(ordinals)): #Count up.
print("On the", ordinals[day], "day of Christmas")
print("My true love gave to me")
for g in range(day, 0, -1): #Count down.
if g == 1:
if day == 1:
print("A ", end = "")
else:
print("And a ", end = "")
print(gifts[g])
print()
sys.exit(0)
On the first day of Christmas My true love gave to me A partridge in a pear tree. On the second day of Christmas My true love gave to me Two turtledoves And a partridge in a pear tree. On the third day of Christmas My true love gave to me Three French hens Two turtledoves And a partridge in a pear tree. On the fourth day of Christmas My true love gave to me Four colly birds Three French hens Two turtledoves And a partridge in a pear tree. On the fifth day of Christmas My true love gave to me Five golden rings Four colly birds Three French hens Two turtledoves And a partridge in a pear tree. On the sixth day of Christmas My true love gave to me Six geese a-laying Five golden rings Four colly birds Three French hens Two turtledoves And a partridge in a pear tree. On the seventh day of Christmas My true love gave to me Seven swans a-swimming Six geese a-laying Five golden rings Four colly birds Three French hens Two turtledoves And a partridge in a pear tree. On the eighth day of Christmas My true love gave to me Eight maids a-milking Seven swans a-swimming Six geese a-laying Five golden rings Four colly birds Three French hens Two turtledoves And a partridge in a pear tree. On the ninth day of Christmas My true love gave to me Nine ladies dancing Eight maids a-milking Seven swans a-swimming Six geese a-laying Five golden rings Four colly birds Three French hens Two turtledoves And a partridge in a pear tree. On the tenth day of Christmas My true love gave to me Ten lords a-leaping Nine ladies dancing Eight maids a-milking Seven swans a-swimming Six geese a-laying Five golden rings Four colly birds Three French hens Two turtledoves And a partridge in a pear tree. On the eleventh day of Christmas My true love gave to me Eleven pipers piping Ten lords a-leaping Nine ladies dancing Eight maids a-milking Seven swans a-swimming Six geese a-laying Five golden rings Four colly birds Three French hens Two turtledoves And a partridge in a pear tree. On the twelfth day of Christmas My true love gave to me Twelve drummers drumming Eleven pipers piping Ten lords a-leaping Nine ladies dancing Eight maids a-milking Seven swans a-swimming Six geese a-laying Five golden rings Four colly birds Three French hens Two turtledoves And a partridge in a pear tree.
print()
to
if day < len(ordinals) - 1: #after every verse except the last,
print()
if day == 1:
print("A ", end = "")
else:
print("And a ", end = "")
to the following.
See
Conditional
expressions.
print("A " if day == 1 else "And a ", end = "")
"partridge in a pear tree."
is the only gift that contains a period.
The
gifts
list should hold only gifts, not the punctuation at the end of a sentence.
Remove the period, and change the original
if g == 1:
if day == 1:
print("A ", end = "")
else:
print("And a ", end = "")
print(gifts[g])
to the following code,
which steers the computer in one of three possible
directions.
if g > 1:
f = "{}"
elif day == 1:
f = "A {}."
else:
f = "And a {}."
print(f.format(gifts[g]))
"two turtledoves"
contains a number
("two")
while
"partridge in a pear tree"
does not contain a number.
We should have had three parallel lists,
to make sure the items stay in synch.
This is no big deal if we have only 12 items,
but would be more important if we had 1000 items.
Make it look like an Excel spreadsheet.
""" Output the lyrics to "The Twelve Days of Christmas." """ import sys days = [ None, ["first", "one", "partridge in a pear tree"], #"one" is not used ["second", "two", "turtledoves"], ["third", "three", "French hens"], ["fourth", "four", "colly birds"], ["fifth", "five", "golden rings"], ["sixth", "six", "geese a-laying"], ["seventh", "seven", "swans a-simming"], ["eighth", "eight", "maids a-milking"], ["ninth", "nine", "ladies dancing"], ["tenth", "ten", "lords a-leaping"], ["eleventh", "eleven", "lords a-leaping"], ["twelfth", "twelve", "drummers drumming"] ] for day in range(1, len(days)): #Count up. print("On the", days[day][0], "day of Christmas") print("My true love gave to me") for d in range(day, 0, -1): #Count down. if d > 1: ordinal = days[d][1] elif day == 1: ordinal = "a" else: ordinal = "and a" print(ordinal.capitalize(), days[d][2], end = "") print("." if d == 1 else "") if day < len(days) - 1: #after every verse except the last, print() sys.exit(0)