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?对列表深拷贝就是无论怎样改动新列表（单维or多维），原列表都不变。
?而下面的浅拷贝，对于多维列表，只是第一维深拷贝了（嵌套的List保存的是地址，复制过去的时候是把地址复制过去了），所以说其内层的list元素改变了，原列表也会变。
🦄浅拷贝（下面均是只对第一层进行深拷贝）：
?1. for循环依次赋值：
old = [1, [1, 2, 3], 3]
new = []
for i in range(len(old)):
new.append(old[i])
new[0] = 3
new[1][0] = 3
print(old)
print(new)
'''
[1, [3, 2, 3], 3]
[3, [3, 2, 3], 3]
'''
?2. 使用copy()函数
old = [1,[1,2,3],3]
new = old.copy()
new[0] = 3
new[1][0] =3
print(old)
print(new)
'''
[1, [3, 2, 3], 3]
[3, [3, 2, 3], 3]
'''
?3. 使用列表生成式：
old = [1,[1,2,3],3]
new = [i for i in old]
new[0] = 3
new[1][0] = 3
print(old)
print(new)
'''
[1, [3, 2, 3], 3]
[3, [3, 2, 3], 3]
'''
?4. 使用索引 [:]
old = [1,[1,2,3],3]
new = old[:]
new[0] = 3
new[1][0] = 3
print(old)
print(new)
'''
[1, [3, 2, 3], 3]
[3, [3, 2, 3], 3]
'''
浅拷贝对于单层列表就是深拷贝，如：
old = [1,2,3]
new = old[:]
new[0] = 666
print(old)
print(new)
"""
[1, 2, 3]
[666, 2, 3]
"""
🦄深拷贝：
使用用deepcopy()方法，才是真正的复制了一个全新的和原列表无关的：
import copy
old = [1,[1,2,3],3]
new = copy.deepcopy(old)
new[0] = 3
new[1][0] = 3
"""
[1, [1, 2, 3], 3]
[3, [3, 2, 3], 3]
"""
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