擅长:python、mysql、java
<p>Python<a href="http://docs.python.org/2/library/stdtypes.html#truth-value-testing" rel="noreferrer">truth-value testing</a>声明将下列值视为<code>False</code>:</p>
<blockquote>
<ul>
<li>zero of any numeric type, for example, 0, 0L, 0.0, 0j.</li>
</ul>
</blockquote>
<p>Numpy可能选择坚持这种行为,并防止NaN在布尔上下文中计算到<code>False</code>。但是请注意,您可以使用<a href="http://docs.scipy.org/doc/numpy/reference/generated/numpy.isnan.html" rel="noreferrer">^{<cd3>}</a>来测试NaN。</p>