擅长:python、mysql、java
<p>元组不是用括号括起来的字符串。要创建一个单项元组,您需要一个尾随逗号:</p>
<pre><code>>>> ('single element') # this is not a tuple, it's a string
'single element'
>>> ('single element',) # note the trailing comma
('single element',)
</code></pre>
<p>有关更多信息,请参阅<a href="http://wiki.python.org/moin/TupleSyntax" rel="nofollow noreferrer">Tuple Syntax</a>堆栈溢出问题<a href="https://stackoverflow.com/questions/7992559/python-tuple-comma-syntax-rule">Python tuple comma syntax rule</a>上的wiki。在</p>