Python学习日志-5

今天分享的是第六章的要点和部分课后习题的参考代码。

要点：

1、字典的概念与使用.

2、字典中添加键-值对.

3、字典的修改.

4、字典中删除键-值对.

5、字典的遍历(item()返回键-值对的列表、keys()返回键的列表、values()返回值的列表).

6、字典不关心排列顺序，只关心键和值的对应关系.

7、通过sorted（）实现按顺序遍历字典.

8、字典和列表的相互嵌套.

参考代码：

6-1

user = {
	"first_name" : "Jay",
	"last_name"  : "Zhou",
	"age" : 35,
	"city" : "Taiwan"
 	}

for key,value in user.items():
 	print(key + " : " + str(value))

运行结果：

first_name : Jay
last_name : Zhou
age : 35
city : Taiwan
[Finished in 0.0s]

6-2

favorite_number = {
	"Bob" : 1,
	"Jay" : 2,
	"May" : 3,
	"Lily" : 4,
	"Lucy" :5
}

for key, value in favorite_number.items():
	print(key + "'s favorite number is " + str(value))

运行结果

Bob's favorite number is 1
Jay's favorite number is 2
May's favorite number is 3
Lily's favorite number is 4
Lucy's favorite number is 5
[Finished in 0.0s]

6-3

dictionary = {
	"GCC" : "A kind of compiler for C",
	"binary" : "A data format using 1 and 0",
	"assembly language" : "A kind of low-level language",
	"python" : "A kind of high-level language",
	"Xcode" : "An IDE for OSX"
}

for key, value in dictionary.items():
	print(key + " : " + value)

运行结果：

GCC : A kind of compiler for C
binary : A data format using 1 and 0
assembly language : A kind of low-level language
python : A kind of high-level language
Xcode : An IDE for OSX
[Finished in 0.0s]

6-4（略，在6-3已经完成）

6-5

rivers = {
	"Nile" : "Egypt",
	"Yangtse" : "China",
	"Ganges" : "India"
}


for river, country in rivers.items():
	print(river + " run through " + country)


for river in rivers.keys():
	print(river);


for country in rivers.values():
	print(country)

运行结果

Nile run through Egypt
Yangtse run through China
Ganges run through India
Nile
Yangtse
Ganges
Egypt
China
India
[Finished in 0.0s]

6-6

favorite_languages = {
	'jen' : 'python',
	'sarah' : 'c',
	'edward' : 'ruby',
	'phil' : 'python'
}

names = ['jen', 'sarah', 'jack', 'cook']

for name in favorite_languages.keys():
	if name in names:
		print("Thank you for being interviewed.")
	else:
		print(name + ", would you like to tell us your favorite language?")

运行结果：

Thank you for being interviewed.
Thank you for being interviewed.
edward, would you like to tell us your favorite language?
phil, would you like to tell us your favorite language?
[Finished in 0.0s]

6-7

user1 = {
	"first_name" : "Jay",
	"last_name"  : "Zhou",
	"age" : 35,
	"city" : "Taiwan"
 	}

user2 = {
	"first_name" : "Bob",
	"last_name"  : "Black",
	"age" : 25,
	"city" : "Guangzhou"
 	}

user3 = {
	"first_name" : "Lucy",
	"last_name"  : "Blair",
	"age" : 15,
	"city" : "Hangzhou"
 	}

people = [user1, user2, user3]

for item in people:
	print('\n')
	for key,value in item.items():
 		print(key + " : " + str(value))

运行结果：

first_name : Jay
last_name : Zhou
age : 35
city : Taiwan


first_name : Bob
last_name : Black
age : 25
city : Guangzhou


first_name : Lucy
last_name : Blair
age : 15
city : Hangzhou
[Finished in 0.0s]

6-8

pet1 = {
	"name" : "Bob",
	"owner" : "Lucy",
	"type" : "dog"
}

pet2 = {
	"name" : "Lily",
	"owner" : "Jack",
	"type" : "cat"
}

pet3 = {
	"name" : "Oliver",
	"owner" : "May",
	"type" : "pig"
}

pets = [pet1, pet2, pet3]

for item in pets:
	print('\n')
	for key,value in item.items():
 		print(key + " : " + value)

运行结果：

name : Bob
owner : Lucy
type : dog


name : Lily
owner : Jack
type : cat


name : Oliver
owner : May
type : pig
[Finished in 0.0s]

6-9

peoples = {
	"Jay" : ["Guangzhou", "Shanghai", "Beijing"],
	"May" : ["Nanjing", "Chengdu"],
	"Bob" : ["Hubei"]
}

for name, places in peoples.items():
	print(name)
	print(places)
	print()

运行结果：

Jay
['Guangzhou', 'Shanghai', 'Beijing']

May
['Nanjing', 'Chengdu']

Bob
['Hubei']

[Finished in 0.0s]

6-10（略，类似于6-9）

6-11（略，类似于6-9，不过是字典嵌套字典）

6-12（略）

要点：

参考代码：

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