If I run the following code in a Python interpreter: <pre class="prettyprint"><code>>>> object.__dict__ is object.__dict__ False </code></pre> Why is the result <code>False</code>?

<code>object.__dict__</code>, unlike other <code>__dict__</code>s, returns a <code>mappingproxy</code> object (a <code>dict_proxy</code> in Python 2). These are created on the fly when <code>__dict__</code> is requested. So as a result, you get a new proxy every time you access <code>object.__dict__</code>. They all proxy the same underlying object, but the proxy is a fresh one all the time. That’s why you can’t get two identical ones.

Why is "object.dict is object.dict" False?

Tags:

python

If I run the following code in a Python interpreter:

>>> object.__dict__ is object.__dict__
False

Why is the result False?

583

asked Oct 21 '15 14:10

NathaneilCapital

1 Answers

object.__dict__, unlike other __dict__s, returns a mappingproxy object (a dict_proxy in Python 2). These are created on the fly when __dict__ is requested. So as a result, you get a new proxy every time you access object.__dict__. They all proxy the same underlying object, but the proxy is a fresh one all the time. That’s why you can’t get two identical ones.