字节数组和列表的区别 [英] Difference between bytearray and list

问题描述

bytearray 和例如 list 或 tuple 之间有什么区别?

顾名思义，bytearray 必须是一个带有byte 对象的array.
在python中，似乎bytes和str被同等对待

<预><代码>>>>字节<输入'str'>

那么，有什么区别呢?
另外，如果你打印一个bytearray，结果很奇怪

<预><代码>>>>v = bytearray([200, 201])>>>打印 vÈÉ

它似乎转换了 chr(integer) 中的整数，对吗?bytearray 那么有什么用呢?

解决方案

在某些方面你是对的:在 Python 2 中，bytes 是 str 类型的同义词.这是因为最初没有 bytes 对象，只有 str 和 unicode(后者用于 unicode 字符串，即具有多个字节能力).当 Python 3 出现时，他们改变了整个字符串的东西，并使 unicode 成为默认的 Python 3 str 类型，并且他们添加了 bytes 作为原始字节序列的类型(使其等效到 Python 2 的 str 对象).

因此，虽然在 Python 3 中 str 和 bytes 有所不同，但 Python 2 中的相应类型是 unicode 和 str.

现在让 bytearray 类型有趣的是它是可变的.上面的所有字符串和字节序列都是不可变的，因此每次更改时，您都在创建一个新对象.但是您可以修改 bytearray 对象，使它们在您需要修改序列中的单个字节的各种用途中变得有趣.

What is the difference between bytearray and for example, a list or tuple?

As the name suggests, bytearray must be an array that carries byte objects.
In python, it seems that bytes and str are treated equally

>>> bytes
<type 'str'>

So, what is the difference?
Also, if you print a bytearray, the result is pretty weird

>>> v = bytearray([200, 201])
>>> print v
ÈÉ

It seems that it transforms the integer in chr(integer) , is that right? What is the use of a bytearray then?

解决方案

You are correct in some way: In Python 2, bytes is synonymous with the str type. This is because originally, there was no bytes object, there was only str and unicode (the latter being for unicode string, i.e. having multi-byte capabilities). When Python 3 came, they changed the whole string things and made unicode the default Python 3 str type, and they added bytes as the type for raw byte sequences (making it equivalent to Python 2’s str object).

So while in Python 3 you differ between str and bytes, the corresponding types in Python 2 are unicode and str.

Now what makes the bytearray type interesting is that it’s mutable. All string and byte sequences above are immutable, so with every change, you are creating a new object. But you can modify bytearray objects, making them interesting for various purposes where you need to modify individual bytes in a sequence.

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