Python中的指针是什么？Python中存在指针吗？

低级编程语言，如C或C++，经常使用指针来直接处理内存。它们能够实现有效的内存管理和低级数据操作。

The low-level complexities of memory administration are abstracted away in Python, a high-level language. Because of this, Python lacks express pointers in an equal manner that C or C++. As an alternative, Python makes use of an idea comparable to this one known as references, which enables indirect access to objects in memory by variables. Python gives builders a sturdy toolkit without requiring them to have a thorough appreciation of low-level memory administration through the use of references and other high-level abstractions.

在Python中，一切都是对象，对象保存在内存中。实际上，当你在Python中定义一个变量时，你正在创建一个对对象的引用。这个引用实际上充当了指向对象在内存中存储位置的指针。

考虑下面的代码，例如。

a = 5
b = a

• a = 5 − The Python statement "a = 5" declares a new variable and gives it the integer value of 5. Python produces a new integer object with the value 5 when this line is performed, and it then assigns a reference to that object to the variable a.

• b = a − In a comparable way, the statement b = a declares a new variable b and offers it the value of a. Since an object (in this case, an integer object with value 5) is referenced through an object (a), then object (b) is likewise referenced by using an object (a). As a result, references to the identical 5-valued integer object are now shared by way of each a and b.

This is important because it means that changes made to a will also be reflected in b since they are both referencing the same object. For example −

Example

a = 5
b = a
a = 6
print(b)

Output

5

As anticipated, yes? To understand the code sample above, follow these easy steps −

• a = 5 − 这行代码创建了一个名为a的新变量，并将其赋值为5。

• b = a − A new variable b is created and assigned the value of a. Variable b holds the integer value of 5 which is the same as variable a.

• a = 6 − This changes the integer value of the variable a to a new value of 6. A now has a reference to a different integer object than b at this time.

• print(b) − This commands outputs b's value to the console. The output of this line is 5 since b still has a reference to the initial integer object with the value of 5.

Memory management is an essential issue of programming, and Python makes use of computerized garbage collection to manage it. The garbage collector of Python takes care of memory allocation and deallocation automatically whereas, in C or C++, developers take the responsibility for memory management.

Python的垃圾回收器会在不再需要通过变量引用的对象时自动从内存中删除它们。

This eliminates the want for guided memory management and frees builders to center their attention on writing code, rather than being traumatic about releasing memory. Ultimately, Python's automatic garbage series provides an extra simple and much less error-prone way of handling reminiscence management.

结论

总之，Python不再像C或C++那样有显式指针，但它使用引用，这是可比较的概念。Python将所有东西都作为对象提供，变量作为指向这些对象的指针。因此，每当您将一个值赋给一个变量，这意味着您正在指向内存中的某个东西。理解Python的引用系统很重要，因为它是语言管理内存的关键组成部分。

通过理解引用，您可以更好地了解通过引用它们的变量传播对象的修改方式。这可以帮助您编写更高效和有利的代码，并避免与内存管理相关的常见陷阱。因此，了解引用是成为熟练的Python程序员的重要一步。

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