整数文字是 Python 中的对象吗?

问题描述

可能的重复:
访问python int文字方法

Python 中的一切都是对象.即使是数字也是一个对象:

>>>a=1>>>类型(一)<类'int'>>>>a.real1

我尝试了以下方法，因为我们应该能够访问对象的类成员:

>>>类型(1)<类'int'>>>>1.真实文件<stdin>"，第 1 行1.真实^语法错误:无效语法

为什么这不起作用?

解决方案

是的，整数文字是 Python 中的对象.总而言之，解析器需要能够理解它正在处理一个整数类型的对象，而语句 1.real 使解析器误以为它有一个浮点 1.code> 后跟单词 real，因此会引发语法错误.

要测试这个，你也可以试试

>>(1).真实1

还有，

>>1.0.real1.0

所以在 1.real 的情况下，python 将 . 解释为小数点.

编辑

BasicWolf 也说得很好 - 1. 被解释为 1 的浮点表示，所以 1.real 等价于编写 (1.)real - 所以没有属性访问运算符，即句号/句号.因此语法错误.

进一步编辑

正如 mgilson 在他/她的评论中提到的那样:解析器可以处理对 int 的属性和方法的访问，但前提是该语句清楚地表明它被赋予了一个 int 而不是 float.

Everything in Python is an object. Even a number is an object:

>>> a=1
>>> type(a)
<class 'int'>
>>>a.real
1

I tried the following, because we should be able to access class members of an object:

>>> type(1)
<class 'int'>
>>> 1.real
  File "<stdin>", line 1
    1.real
         ^
SyntaxError: invalid syntax

Why does this not work?

解决方案

Yes, an integer literal is an object in Python. To summarize, the parser needs to be able to understand it is dealing with an object of type integer, while the statement 1.real confuses the parser into thinking it has a float 1. followed by the word real, and therefore raises a syntax error.

To test this you can also try

>> (1).real
  1

as well as,

>> 1.0.real
  1.0

so in the case of 1.real python is interpreting the . as a decimal point.

Edit

BasicWolf puts it nicely too - 1. is being interpreted as the floating point representation of 1, so 1.real is equivalent to writing (1.)real - so with no attribute access operator i.e. period /full stop. Hence the syntax error.

Further edit

As mgilson alludes to in his/her comment: the parser can handle access to int's attributes and methods, but only as long the statement makes it clear that it is being given an int and not a float.

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