Average of a numpy array returns NaN : <p>I have an np.array with over 330,000 rows. I simply try to take the average of it and it returns NaN. Even if I try to filter out any potential NaN values in my array (there shouldn't be any anyways), average returns NaN. Am I doing something totally wacky? </p>

<p>My code is here: </p>

<pre><code>average(ngma_heat_daily)
Out[70]: nan

average(ngma_heat_daily[ngma_heat_daily != nan])
Out[71]: nan
</code></pre>
