Python编程：列表 [英] Python programming: lists

问题描述

gene = [0,5,1,0,7,1]

originalGene = gene



gene [0] = 2

打印originalGene



输出：[2,5,1,0,7,1]

问题：为什么'originalGene'列表的内容也会改变？



我尝试过：



我试图多次运行代码，我尝试使用变量进行操作，但它与变量一起工作，但没有列表......

gene = [0, 5, 1, 0, 7, 1]
originalGene = gene

gene[0] = 2
print originalGene

OUTPUT: [2, 5, 1, 0, 7, 1]
QUESTION: Why do the contents of the 'originalGene' list get changed as well ?

What I have tried:

I have tried to run the code multiple times and I have tried doing it with variables and it WORKS with variables but not with lists...

推荐答案

可能是因为 originalGene 和 gene 都是真实列表的指针，所以当 gene [0] = 2 更改列表的第一个元素，它似乎同时更改两个变量。

你需要学习python更多细节。

It is probably because originalGene and gene are both pointers to the real list, so when gene[0] = 2 change the first element of the list, it appear to change both variables at same time.
You need to study python for more details.

你应该复制一份：

You should take a copy:

gene = [0, 5, 1, 0, 7, 1] 
originalGene = gene[:]

gene = [0,5,1,0,7,1]

originalGene = gene



这就是原因。两者都指向同一个列表。查看这两个列表的ID。它应该是相同的。

gene = [0, 5, 1, 0, 7, 1]
originalGene = gene

This is the reason. Both points to the same list. Check out id of both these list. It should be same.

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