脚本语言中变量的内存分配是如何进行的? [英] How is the memory allocation done for variables in scripting languages?

问题描述

例如，在javascript中

For example, in javascript

我可以说

var x = 5;

以后我可以做

x = 'a';

然后

x = "hello";

那么，如何为变量分配内存?事实上，所有变量都有一个共同的类型var"，变量的值可以在运行时改变，如上所示.为这些变量分配和管理内存不是一项艰巨的任务吗?到底是怎么做的?

So, how is memory allocated for the variables? As it is, all variables have a common type 'var' and values of variables can change at run-time as seen above. Isn't it a difficult task to allocate and manage memory for these variables? Exactly, how is it done?

推荐答案

Python 使用一种称为 引用计数的技术，它基本上在值中放置了一个计数器.每次创建对值的引用时，计数器都会递增.当对该值的引用丢失时(例如，当您为 'x' 分配一个新值时)，该值将递减.当计数器达到零时，这意味着不存在对该值的引用，并且它可以被释放.这是一个简化的解释，但至少是基础知识.

Python uses a technique called reference counting, which basically puts a counter in the value. Each time a reference to a value is created, the counter is incremented. When a reference to the value is lost (for instance when you assign a new value to 'x'), the value is decremented. When the counter reaches zero, that means that no reference to the value exists, and it can be deallocated. This is a simplified explanation, but that's at least the basics.

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