Add metadata comment to Numpy ndarray : <p>I have a Numpy ndarray of three large arrays and I'd just like to store the path to the file that generated the data in there somewhere. Some toy data:</p>

<pre><code>A = array([[  6.52479351e-01,   6.54686928e-01,   6.56884432e-01, ...,
              2.55901861e+00,   2.56199503e+00,   2.56498647e+00],
           [             nan,              nan,   9.37914686e-17, ...,
              1.01366425e-16,   3.20371075e-16,  -6.33655223e-17],
           [             nan,              nan,   8.52057308e-17, ...,
              4.26943463e-16,   1.51422386e-16,   1.55097437e-16]],                 
           dtype=float32)
</code></pre>

<p>I can't just append it as an array to the ndarray because it needs to be the same length as the other three. </p>

<p>I could just append <code>np.zeros(len(A[0]))</code> and make the first value the string so that I can retrieve it with A[-1][0] but that seems ridiculous.</p>

<p>Is there some metadata key I can use to store a string like <code>/Documents/Data/foobar.txt'</code> so I can retrieve it with something like <code>A.metadata.comment</code>?</p>

<p>Thanks!</p>
