擅长：python、mysql、java
<p>一旦您扩展了slices，一定要理解未被充分理解的<a href="http://docs.python.org/library/functions.html#slice" rel="nofollow noreferrer">slice()</a>函数：</p>
<pre><code>>>> for sl in [(1,-1),(0,20,3),(10,),(None,None,-3),(None,None,4)]:
... print range(20)[slice(*sl)]
...
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18]
[0, 3, 6, 9, 12, 15, 18]
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[19, 16, 13, 10, 7, 4, 1]
[0, 4, 8, 12, 16]
</code></pre>
<p>它对于<a href="https://stackoverflow.com/questions/3911483/python-slice-how-to-i-know-the-python-slice-but-how-can-i-use-built-in-slice-ob">fixed length data</a>格式特别有用。在</p>
