技術標籤：Pythonpython

6字典

6.1一個簡單的字典

alien_0 = {'color':'blue','points':5}
print(alien_0)
print(alien_0['color'])
print(alien_0['points'])

{‘color’: ‘blue’, ‘points’: 5}
blue
5

6.2使用字典

6.2.1訪問字典中元素

alien_0 = {'color':'blue','points':5}
new_points = alien_0['points']
print("You have earned "+str
 
(new_points)+" points")

You have earned 5 points

6.2.2給字典新增新的鍵值對

# 給外星人新增x，y座標
alien_0 = {'color':'blue','points':5}
alien_0['x_points']=0
alien_0['y_points']=0.8
print(alien_0)

{‘color’: ‘blue’, ‘points’: 5, ‘x_points’: 0, ‘y_points’: 0.8}

6.2.3先建立一個空字典

alien_0 = {}
#分行新增各個鍵值對
alien_0['color'] =
 
 'red'
alien_0['points'] = 5
print(alien_0)

{‘color’: ‘red’, ‘points’: 5}

6.2.4修改字典中的值

alien_0 = {'color':'red'}
print("The alien color is "+alien_0['color'])

#修改值
alien_0['color'] = 'yellow'
print("The alien color now is "+alien_0['color'])

The alien color is red
The alien color now is yellow

6.2.5刪除字典中的鍵值對

alien_0 = {'color':'blue','points':5}
del alien_0['color']
print(alien_0)

{‘points’: 5}

6.3遍歷字典

6.3.1遍歷所有鍵值對

user = {
    'uesrname':'admin',
    'password':'123456',
    'age':'20',
    'major':'Computer Science'
}
for key,value in user.items():
    print("\nKey：",key)
    print("Value：",value)

Key： uesrname
Value： admin

Key： password
Value： 123456

Key： age
Value： 20

Key： major
Value： Computer Science

6.3.2遍歷所有鍵

user = {
    'uesrname':'admin',
    'password':'123456',
    'age':'20',
    'major':'Computer Science'
}
for key in user.keys():
    print(key)

uesrname
password
age
major

6.3.3按順序遍歷所有鍵

user = {
    'uesrname':'admin',
    'password':'123456',
    'age':'20',
    'major':'Computer Science'
}
for key in sorted(user.keys()):
    print(key)

age
major
password
uesrname

6.3.4遍歷所有值

user = {
    'uesrname':'admin',
    'password':'123456',
    'age':'20',
    'major':'Computer Science'
}
for value in user.values():
    print(value)

admin
123456
20
Computer Science

6.4巢狀

6.4.1字典列表

alien_0 = {'color':'red','points':5}
alien_1 = {'color':'blue','points':10}
alien_2 = {'color':'yellow','points':15}
aliens = [alien_0,alien_1,alien_2]
for alien in aliens:
    print(aliens)

[{‘color’: ‘red’, ‘points’: 5}, {‘color’: ‘blue’, ‘points’: 10}, {‘color’: ‘yellow’, ‘points’: 15}]
[{‘color’: ‘red’, ‘points’: 5}, {‘color’: ‘blue’, ‘points’: 10}, {‘color’: ‘yellow’, ‘points’: 15}]
[{‘color’: ‘red’, ‘points’: 5}, {‘color’: ‘blue’, ‘points’: 10}, {‘color’: ‘yellow’, ‘points’: 15}]

6.4.2在字典中儲存列表

pizza = {
    'crust':'thick',
    'toppings':['mushrooms','extra cheese']
}
print(pizza['toppings'])

[‘mushrooms’, ‘extra cheese’]

6.4.3在字典中儲存字典

users = {
    'tom':{
        'age': 21,
        'password':'123456',
        'location':'zhengzhou'
    },
    'jerry':{
        'age': 22,
        'password':'123456',
        'location':'beijing'
    },
}
for userName,userInfo in users.items():
    print("\nUsername："+userName)
    user_age = str(userInfo['age'])
    user_password = userInfo['password']
    user_location = userInfo['location']
    print("\nAge："+user_age)
    print("\nPassword："+user_password)
    print("\nLocation："+user_location)
    print("\n==============================")

Username：tom

Age：21

Password：123456

Location：zhengzhou

==============================

Username：jerry

Age：22

Password：123456

Location：beijing

==============================