The variable type immutable type
Variable type: value changes, the same memory address, to prove in changing the original
Immutable type: when the value changes, the memory address is also changed, i.e. becomes id, proved to be not changing the original value, is to produce a new value
1. Digital Type
>>> x = 10
>>> id(x)
1830448896
>>> x = 20
>>> id(x)
1830448928
# 内存地址改变了，说明整型是不可变数据类型，浮点型也一样
2. String
>>> x = "Jy"
>>> id(x)
938809263920
>>> x = "Ricky"
>>> id(x)
938809264088
# 内存地址改变了，说明字符串是不可变数据类型
3. List
>>> list1 = ['tom','jack','egon']
>>> id(list1)
486316639176
>>> list1[2] = 'kevin'
>>> id(list1)
486316639176
>>> list1.append('lili')
>>> id(list1)
486316639176
# 对列表的值进行操作时，值改变但内存地址不变，所以列表是可变数据类型
4. tuple
>>> t1 = ("tom","jack",[1,2])
>>> t1[0]='TOM' # 报错：TypeError
>>> t1.append('lili') # 报错：TypeError
# 元组内的元素无法修改，指的是元组内索引指向的内存地址不能被修改
>>> t1 = ("tom","jack",[1,2])
>>> id(t1[0]),id(t1[1]),id(t1[2])
(4327403152, 4327403072, 4327422472)
>>> t1[2][0]=111 # 如果元组中存在可变类型，是可以修改，但是修改后的内存地址不变
>>> t1
('tom', 'jack', [111, 2])
>>> id(t1[0]),id(t1[1]),id(t1[2]) # 查看id仍然不变
(4327403152, 4327403072, 4327422472)
5. Dictionary
>>> dic = {'name':'egon','sex':'male','age':18}
>>>
>>> id(dic)
4327423112
>>> dic['age']=19
>>> dic
{'age': 19, 'sex': 'male', 'name': 'egon'}
>>> id(dic)
4327423112
# 对字典进行操作时，值改变的情况下，字典的id也是不变，即字典也是可变数据类型
6. Data Type Summary
