Python 中的一切都是对象，以下代码：
赋值赋值只是简单地使新变量指向已经存在的对象：
numbers = [1, 2, 3, 4, 5] new_numbers = numbers
numbers 与 new_numbers 指向相同的对象，修改 numbers 就是在修改 new_numbers 。
id(numbers) == id(b) 或者 numbers is new_numbers 都为 True.
浅拷贝和深拷贝之间的区别仅与复合对象（包含其他对象的对象，如列表或类实例）相关。
浅拷贝复制得到新的复合对象，但引用原始对象的元素。
深拷贝复制得到新的复合对象，并复制该组成原始对象的元素。
要复制对象，需要使用内建模块 copy
调用 copy.copy() 实现浅拷贝：import copy old_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] shallow_list = copy.copy(old_list) print(old_list) print(shallow_list) print(old_list is shallow_list) print(old_list[0] is shallow_list[0]) old_list[0][0] = "x" print(old_list) print(shallow_list)
输出：
[[1, 2, 3], [4, 5, 6], [7, 8, 9]] [[1, 2, 3], [4, 5, 6], [7, 8, 9]] False True [['x', 2, 3], [4, 5, 6], [7, 8, 9]] [['x', 2, 3], [4, 5, 6], [7, 8, 9]]调用 copy.deepcopy() 实现浅拷贝：
old_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] deep_list = copy.deepcopy(old_list) print(old_list) print(deep_list) print(old_list is deep_list) print(old_list[0] is deep_list[0]) old_list[0][0] = "x" print(old_list) print(deep_list)
输出：
[[1, 2, 3], [4, 5, 6], [7, 8, 9]] [[1, 2, 3], [4, 5, 6], [7, 8, 9]] False False [['x', 2, 3], [4, 5, 6], [7, 8, 9]] [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
