在python中创建一个新类型 [英] Create a new type in python

问题描述

在 Python 3.x 中有没有办法创建一个新类型?我只能找到在 C++ 中做到这一点的方法.(顺便说一句，我的意思不是添加/编辑语法)

基本上我想做的是创建一个词法分析器，在那里我扫描输入，python 已经可以做 int 和 string，但是如果我想要另一种数据类型，例如 name，我该如何分配它以便我可以做...

示例:

 # 这个是可以的a =字符串"类型(一)><类，'str'># 我怎样才能做到这一点?b = 我的名字类型(我的名字)><类，'名称'>

解决方案

你会想要这样的东西，class.在源代码中，您在 Python 中看到的所有对象类型都采用 class 形式.

<预><代码>>>>类我的名字:... def __init__(self, name):... self.name = 姓名... def __str__(self):...返回 self.name...>>>b = myName('约翰')>>>类型(b)<class '__main__.myName'>>>>打印(b)约翰

输出与您预期的略有不同的原因是因为 class 的名称是 myName 所以这就是 type() 返回的.我们还在 class 名称之前得到 __main__. 因为它是当前模块的本地名称.

Is there a way in Python 3.x to create a new type? I can only find ways to do it in c++. (I don't mean adding/editing syntax by the way)

Basically what I want to do is create a lexer, where I scan input and python can already do int and string, but if I want another datatype such as name, how could I assign it so that I can do...

Example:

    # This can be done
    a = "string"
    type(a)
    > <class, 'str'>

    # How can I do this?
    b = myName
    type(myName)
    > <class, 'name'>

解决方案

You would want something like this, a class. In the source code all of the object types you see in Python are in class form.

>>> class myName:
...     def __init__(self, name):
...         self.name = name
...     def __str__(self):
...         return self.name
...

>>> b = myName('John')
>>> type(b)
<class '__main__.myName'>
>>> print(b)
John

The reason the output is slightly different to what you expected is because the name of the class is myName so that is what is returned by type(). Also we get the __main__. before the class name because it is local to the current module.

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