title: Size of data type using NumPy
body: <p>In NumPy, I can get the size (in bytes) of a particular data type by:</p>
  
  <pre><code>datatype(...).itemsize
  </code></pre>
  
  <p>or:</p>
  
  <pre><code>datatype(...).nbytes
  </code></pre>
  
  <p>For example:</p>
  
  <pre><code>np.float32(5).itemsize #4
  np.float32(5).nbytes   #4
  </code></pre>
  
  <p>I have two questions. First, is there a way to get this information <em>without creating an instance</em> of the datatype? Second, what's the difference between <code>itemsize</code> and <code>nbytes</code>?</p>