擅长:python、mysql、java
<p>你需要读一下:<a href="https://docs.python.org/2/library/stdtypes.html#truth-value-testing" rel="nofollow noreferrer">https://docs.python.org/2/library/stdtypes.html#truth-value-testing</a></p>
<pre><code>'foo' == True # -> False
'' == True # -> False
'' == False # -> False
</code></pre>
<p>总是<code>False</code>。字符串不等于<code>bool</code>。但是-是-<code>bool('non-empty-str') -> True</code>;<code>bool('') -> False</code>。你知道吗</p>
<p>你还有其他的“秘密”。你知道吗</p>
<p><code>is</code>比较两个物体的身份<code>id()</code>(这里也有一些谜团:<a href="https://stackoverflow.com/questions/15171695/weird-integer-cache-inside-python-2-6">What's with the Integer Cache inside Python?</a>)</p>
<p>这可能也很有趣:<a href="https://stackoverflow.com/questions/2764017/is-false-0-and-true-1-in-python-an-implementation-detail-or-is-it-guarante">Is False == 0 and True == 1 in Python an implementation detail or is it guaranteed by the language?</a></p>