Python拷贝分为深拷贝和浅拷贝
浅拷贝对子对象不拷贝，深python基础教程拷贝全部拷贝
l1 = [1, 2, [3, 4]]
l2 = copy.copy(l1)
l1.append(5)
l1[2].append(5) # 子对象 改变
print(l1)
print(l2)
--------------
[1, 2, [3, 4, 5], 5]
[1, 2, [3, 4, 5]]
深拷贝完是两个完全不相干的对象
l1 = [1, 2, [3, 4]]
l2 = copy.deepcopy(l1)
l1.append(5)
l1[2].append(5)
print(l1)
print(l2)
--------------
[1, 2, [3, 4, 5], 5]
[1, 2, [3, 4]]
