Learn Python The Hard Way-Ecercise36~40

最新推荐文章于 2021-02-26 09:30:01 发布

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本文通过几个具体的Python编程练习来介绍如何操作列表、使用字典及理解类和对象的概念。包括列表的增删改查、字典的动态填充及类实例化的应用。

Exercise36：设计和调试

Exercise37：复习各种符号

Exercise38：列表的操作

ten_things = "Apples Oranges Crows Telephone Light Sugar"

print "Wait there's not 10 things in that list, let's fix that."

stuff = ten_things.split(' ')
more_stuff = ["Day", "Night", "Song", "Frisbee", "Corn", "Banana", "Girl", "Boy"]

while len(stuff) != 10:
	next_one = more_stuff.pop()
	print "Adding: ", next_one
	stuff.append(next_one)
	print "There's %d items now." % len(stuff)

print "There we go: ", stuff
print "Let's do some thing with stuff."

print stuff[1]
print stuff[-1] #whoa!fancy
print stuff.pop()
print ' '.join(stuff) #what? cool!
print '#'.join(stuff[3:5]) #super stellar!

输出结果：

$ python ex38.py
Wait there's not 10 things in that list, let's fix that.
Adding: Boy
There's 7 items now.
Adding: Girl
There's 8 items now.
Adding: Banana
There's 9 items now.
Adding: Corn
There's 10 items now.
There we go: ['Apples', 'Oranges', 'Crows', 'Telephone', 'Light', 'Sugar', 'Boy', 'Girl', 'Banana', 'Corn']
Let's do some things with stuff.
Oranges
Corn
Corn
Apples Oranges Crows Telephone Light Sugar Boy Girl Banana
Telephone#Light

Exercise39：字典，可爱的字典

cities = {'CA': 'San Francisco', 'MI': 'Detroit', 'FL': 'Jacksonville'}


cities['NY'] = 'New York'
cities['OR'] = 'Portland'

def find_city(themap, state):
	if state in themap:
		return themap[state]
	else:
		return "Not found."

# ok pay attention
cities['_find'] = find_city

while True:
	print "State? (ENTER to quit)",
	state = raw_input("> ")

	if not state: break

	# this line is the most import ever! study!
	city_found = cities['_find'](cities, state)
	print city_found

输出结果：

$ python ex39.py
----------
NY State has: New York
OR State has: Portland
----------
Michigan's abbreviation is: MI
Florida's abbreviation is: FL
----------
Michigan has: Detroit
Florida has: Jacksonville
----------
California is abbreviated CA
Michigan is abbreviated MI
New York is abbreviated NY
Florida is abbreviated FL
Oregon is abbreviated OR
----------
FL has the city Jacksonville
CA has the city San Francisco
MI has the city Detroit
OR has the city Portland
NY has the city New York
----------
California state is abbreviated CA and has city San Francisco
Michigan state is abbreviated MI and has city Detroit
New York state is abbreviated NY and has city New York
Florida state is abbreviated FL and has city Jacksonville
Oregon state is abbreviated OR and has city Portland
----------
Sorry, no Texas.
The city for the state 'TX' is: Does Not Exist

Exercise40：模块，类和对象

class Song(object):
	
	def __init__(self, lyrics):
		self.lyrics = lyrics

	def sing_me_a_song(self):
		for line in self.lyrics:
			print line

happy_bday = Song(["Happy birthday to you",
                   "I don't want to get sued",
                   "So I'll stop right there"])

bulls_on_parade = Song(["They rally around the family",
						"with pocket full of shells"])

happy_bday.sing_me_a_song()

bulls_on_parade.sing_me_a_song()

输出结果：

$ python ex40.py
Happy birthday to you
I don't want to get sued
So I'll stop right there
They rally around the family
With pockets full of shells