python 浅拷贝和深拷贝区别

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' a test module '

__author__ = 'Zhang Shuai'

import copy

a = [1, 2, [3, 4], 4]
b = a  # 引用传递，指向同一个内存
c = copy.copy(a)  # 浅拷贝，只拷贝父对象，分配新的内存
d = copy.deepcopy(a)  # 深拷贝，父对象和子对象都拷贝，分配新的内存。
a.append(5)
a[2].append("c")
print("a=", a)
print("b=", b)
print("c=", c)
print("d=", d)

a= [1, 2, [3, 4, 'c'], 4, 5]
b= [1, 2, [3, 4, 'c'], 4, 5]
c= [1, 2, [3, 4, 'c'], 4]
d= [1, 2, [3, 4], 4]