dict

#定义一个空的字典
dic = {}
print(type(dic)) #<class 'dict'>
print(bool(dic)) #False

#定义个带有元素的字典
dic = {'name': 'yjq', 'age': 21, 'sex': '男'}
print(dic)  #{'name': 'yjq', 'age': 21, 'sex': '男'}

 

#打印键
for i in  dic.keys() :
    print('字典键：',i)
"""
字典键： name
字典键： age
字典键： sex
"""
#打印值
for q in dic.values() :
    print('字典的每一个值:',q)
    
"""
字典的每一个值: yjq
字典的每一个值: 21
字典的每一个值: 男
"""

#打印键值对的形式输出
for k,y in dic.items() :
    print(k,'---->',y)

v = dic.values()
y = dic.keys()
print(v,y)
"""
name ----> yjq
age ----> 21
sex ----> 男
"""

#给dic字典添加元素
dic.setdefault('address','四川')
print(dic)
#{'name': 'yjq', 'age': 21, 'sex': '男', 'address': '四川'}
num  = [1,33,3,'dic']
dic.setdefault('数字',num)
print(dic)
#{'name': 'yjq', 'age': 21, 'sex': '男', 'address': '四川', '数字': [1, 33, 3, 'dic']}

 

删除字典的元素值为“男”
v = dic.pop('sex')
print(v,dic)

#修改字典元素的值 gfq
dic['name'] = 'gfq'
print(dic)
#拷贝dic一份数据 名为 date
date = dic.copy()
print('date:',date)
print('dic:',dic)
#把 dic 数据清空
dic.clear()
print('dic:',dic)
#删除字典
# del(dic)
# print(dic)#name 'dic' is not defined

#键不一样只都是一样的
num = [1,3,32,3]
dic1 = dic.fromkeys(num,'数字')
print('jjkkk')
print(dic1)
print('000000000000')

#更新数据
msgq = {'what is you name?':'my name is yangjinquan', 'age': 23, 1 : 1111}
dic1.update(msgq)
print(dic1)

显示结果：

男 {'name': 'yjq', 'age': 21, 'address': '四川', '数字': [1, 33, 3, 'dic']}
{'name': 'gfq', 'age': 21, 'address': '四川', '数字': [1, 33, 3, 'dic']}
date: {'name': 'gfq', 'age': 21, 'address': '四川', '数字': [1, 33, 3, 'dic']}
dic: {'name': 'gfq', 'age': 21, 'address': '四川', '数字': [1, 33, 3, 'dic']}
dic: {}
jjkkk
{1: '数字', 3: '数字', 32: '数字'}
000000000000
{1: 1111, 3: '数字', 32: '数字', 'what is you name?': 'my name is yangjinquan', 'age': 23}