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':'12223@qq.com',

'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)