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导入模块:
>>> import copy
深浅拷贝:
>>> X = copy.copy(Y) #浅拷贝:只拷贝顶级的对象,或者说:父级对象 >>> X = copy.deepcopy(Y) #深拷贝:拷贝所有对象,顶级对象及其嵌套对象。或者说:父级对象及其子对象
例:
>>> D = {‘name‘:‘jack‘,‘age‘:20} >>> C1 = copy.copy(D) >>> C2 = copy.deepcopy(D) >>> id(D);id(C1);id(C2) 53035208 53611144 53610248 >>> D[‘name‘] = ‘tom‘ #改变源 >>> D;C1;C2 {‘age‘: 20, ‘name‘: ‘tom‘} {‘age‘: 20, ‘name‘: ‘jack‘} {‘age‘: 20, ‘name‘: ‘jack‘}
如果有嵌套:
D = {‘name‘:{‘first‘:‘john‘,‘last‘:‘lee‘},‘job‘:[‘IT‘,‘HR‘]} >>> C1 = copy.copy(D) >>> C2 = copy.deepcopy(D) >>> D;C1;C2 {‘job‘: [‘IT‘, ‘HR‘], ‘name‘: {‘first‘: ‘john‘, ‘last‘: ‘lee‘}} {‘job‘: [‘IT‘, ‘HR‘], ‘name‘: {‘first‘: ‘john‘, ‘last‘: ‘lee‘}} {‘job‘: [‘IT‘, ‘HR‘], ‘name‘: {‘first‘: ‘john‘, ‘last‘: ‘lee‘}} >>> id(D);id(C1);id(C2) 53018568 53611592 53610056 >>> >>> D[‘job‘][0] = ‘RRRR‘ #修改其中一个元素 >>> D;C1;C2 {‘job‘: [‘RRRR‘, ‘HR‘], ‘name‘: {‘first‘: ‘john‘, ‘last‘: ‘lee‘}} {‘job‘: [‘RRRR‘, ‘HR‘], ‘name‘: {‘first‘: ‘john‘, ‘last‘: ‘lee‘}} {‘job‘: [‘IT‘, ‘HR‘], ‘name‘: {‘first‘: ‘john‘, ‘last‘: ‘lee‘}}
#结论:
(1)深浅拷贝都是对源对象的复制,占用不同的内存空间
(2)如果源对象只有一级目录的话,源做任何改动,不影响深浅拷贝对象
(3)如果源对象不止一级目录的话,源做任何改动,都要影响浅拷贝,但不影响深拷贝
(4)序列对象的切片其实是浅拷贝,即只拷贝顶级的对象
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原文地址:http://www.cnblogs.com/ping-y/p/5845462.html