title: identifying objects, why does the returned value from id(...) change?
body: <blockquote>
    <h3>id(object)</h3>
    
    <p>This is an integer (or long integer) which is guaranteed to be unique and constant for this object during its lifetime. </p>
  </blockquote>
  
  <p>Can you explain this output? Why does <code>j</code>'s id change?</p>
  
  <pre><code>&gt;&gt;&gt; i=10  
  &gt;&gt;&gt; id(i)  
  6337824  
  &gt;&gt;&gt; j=10  
  &gt;&gt;&gt; id(j)  
  6337824  
  &gt;&gt;&gt; j=j+1  
  &gt;&gt;&gt; id(j)  
  6337800  
  &gt;&gt;&gt; id(i)  
  6337824  
  </code></pre>