尽管元组是不可变的，但它们以交互模式存储在不同的地址中.为什么? [英] Even though tuples are immutable, they are stored in different addresses in interactive mode. Why?

问题描述

t = (1,2,3)
t1 = (1,2,3)
print(id(t))
print(id(t1))

以上代码行在 Python 中的脚本模式下给出了相同的地址，但在交互模式下它输出不同的地址.谁能解释一下这是什么原因?

The above lines of code gives the same addresses in script mode in Python, but in interactive mode it outputs different addresses. Can anyone explain the reason for this?

推荐答案

在编译脚本时，编译器可以搜索所有等价的元组并生成代码以对所有元组使用相同的引用.

When the script is being compiled, the compiler can search for all the equivalent tuples and generate code to use the same reference for all of them.

但在交互模式下，它需要保留所有元组的缓存，以便它可以搜索先前的等效元组并返回对它的引用，而不是每次都创建一个新元组.交互式解释器不这样做.

But in interactive mode, it would need to keep a cache of all tuples so it could search for a previous equivalent tuple and return a reference to it, rather than creating a new tuple each time. The interactive interpreter doesn't do this.

如果将两个变量分配在同一行，实际上会得到相同的元组.

If you assign both variables on the same line, you actually get the same tuple.

t = (1, 2, 3); t1 = (1, 2, 3)

这大概是因为它为每个输入运行编译器，所以它可以做完整的分析和优化.

This is presumably because it's running the compiler for each input, so it can do the full analysis and optimization.

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