python学习字典

#一个简单的字典
student_0={'c_no':'3117370057','sex':'female','name':'daimengyao'}

#访问并打印字典中的值
print(student_0['c_no'])
#添加键值对
student_0['course']='math'
student_0['score']='90'
print(student_0)
#修改字典中的值
student_0['score']='99'
print(student_0)


student_0={'c_no':'3117370057','sex':'female','name':'daimengyao','course':'math','score':99,
'class_rank':15}
print(student_0)
#如果成绩大于等于90，成绩排名增加2，小于90则增加1
if  student_0['score']>=90:
rank_increase=2
else:
rank_increase=1
student_0['class_rank']=student_0['class_rank']+rank_increase
print(student_0['class_rank'])


#删除键值对
del student_0['class_rank']
print(student_0)


#由类似对象组成的字典
favorite_food={
'zhangsan':'apple',
'lisi':'bread',
'wanger':'suger',
'mazi':'beef',
}
print("lisi's favorite_food is "+favorite_food['lisi'])


#遍历所有的键—值对
user_0={
'username':'daidai',
'email':'[email protected]',
'passwd':'123445',
'sex':'female',
}
#key和value可以任意命名
for key,value in user_0.items():
print(key+": "+value)


favorite_food={
'zhangsan':'apple',
'lisi':'bread',
'wanger':'suger',
'mazi':'beef',
}
for k,v in favorite_food.items():
print(k+"' favorite food is "+v)


#遍历字典中的所有键
favorite_food={
'zhangsan':'apple',
'lisi':'bread',
'wanger':'suger',
'mazi':'beef',
}
print("I have do the research among:")
for key in favorite_food.keys():
print(key)
#使用当前键来访问与之相关联的值
favorite_food={
'zhangsan':'apple',
'lisi':'bread',
'wanger':'suger',
'mazi':'beef',

}

friends=['zhangsan','lisi']
for name in favorite_food.keys():
print(name)
if name in friends:

print(name+",is my friend!")

#检查某个人是否在
if 'daidai' not in favorite_food.keys():
print("daidai,can you do the survey")

#遍历字典中的所有值
favorite_food={
'zhangsan':'apple',
'lisi':'bread',
'wanger':'suger',
'mazi':'beef',
}
for food in favorite_food.values():
print(food)


################分界线###############
#字典嵌套
student_1={'name':'daidai','sex':'female','class':'7099','age':23}
student_2={'name':'mengmeng','sex':'male','class':'7098','age':25}
student_3={'name':'yaoyao','sex':'female','class':'7010','age':24}

students=[student_1,student_2,student_3]

for student in students:
print(student)


#代码自动生成学生
students=[]

for student_number in range(15):
new_student={
'name':'yaoyao',
'sex':'female',
'class':'7010',
'age':24,
}
students.append(new_student)
print(students)
#显示创建的学生数
print("Total number of aliens: " + str(len(students)))


################分界线###############
#字典中包含列表
foods={
'fruit':['apple','orange'],
'vegetables':['cabbage','radish'],
'meat':['beef','chicken','pork'],
}
for m in foods['meat']:
print(m)

for key,value in foods.items():
print(key)
print(value)

################分界线###############
#在字典中存储字典
students={
'student_1':{
'name':'daidai',
'sex':'female',
'class':'7099',
'age':23,
},

'student_2':{
'name':'mengmeng',
'sex':'male',
'class':'7098',
'age':25,
},
}
for student,stuinfo in students.items():
print(student)
allinfo=stuinfo['name']+" "+stuinfo['sex']+" "+stuinfo['class']+" "
+str(stuinfo['age'])
print(allinfo)