Python入门篇(三)之列表
names = ["ZhangYang","Guyun",["alex","jack"],"Xiangpeng","Xuliangchen"] names2 = names.copy()print(names)
print(names2)
names = "古云"
names = "ALEX" #更改列表中的alex为ALEX,可以看到names2中也相应更改
print("names-->",names)
print("names2-->",names2)
执行结果:
['ZhangYang', 'Guyun', ['alex', 'jack'], 'Xiangpeng', 'Xuliangchen']
['ZhangYang', 'Guyun', ['alex', 'jack'], 'Xiangpeng', 'Xuliangchen']
names--> ['ZhangYang', '古云', ['ALEX', 'jack'], 'Xiangpeng', 'Xuliangchen']
names2--> ['ZhangYang', 'Guyun', ['ALEX', 'jack'], 'Xiangpeng', 'Xuliangchen']
★★★★注意:这里的的copy只会拷贝第一层,列表中包含列表,其中列表是指向存放列表的内存地址,所以在更改列表中的元素时,拷贝的部分也会相应地更改。
为了实现深入拷贝,可以导入copy模块:
import copy
names2 = copy.deepcopy(names)
print(names)
print(names2)
names = "古云"
names = "ALEX"
print("names-->",names)
print("names2-->",names2)
执行结果:
['ZhangYang', 'Guyun', ['alex', 'jack'], 'Xiangpeng', 'Xuliangchen']
['ZhangYang', 'Guyun', ['alex', 'jack'], 'Xiangpeng', 'Xuliangchen']
names--> ['ZhangYang', '古云', ['ALEX', 'jack'], 'Xiangpeng', 'Xuliangchen']
names2--> ['ZhangYang', 'Guyun', ['alex', 'jack'], 'Xiangpeng', 'Xuliangchen']
可以看到拷贝是完全克隆过来的,但是生产过程中一般不会使用,拷贝多一份数据,等于多占据了一份内存空间。
页:
[1]