擅长:python、mysql、java
<p><a href="http://docs.python.org/reference/lexical_analysis.html#identifiers">Python Language Reference, §2.3, "Identifiers and keywords"</a></p>
<blockquote>
<p>Identifiers (also referred to as <em>names</em>) are described by the following lexical definitions:</p>
<pre><code>identifier ::= (letter|"_") (letter | digit | "_")*
letter ::= lowercase | uppercase
lowercase ::= "a"..."z"
uppercase ::= "A"..."Z"
digit ::= "0"..."9"
</code></pre>
<p>Identifiers are unlimited in length. Case is significant.</p>
</blockquote>