对于字符串的排序,我们知道是比较相同index位置的字符的值来进行的。这样的排序有个问题,就是当被排序的字符串的内容是有数字顺序的,而且还不等长就比较的郁闷了。我们在xp以前的操作系统的资源管理器里,就会常常看到这样的文件名序列:
x1, x10, x11, x12, x13, x14, x15, x16, x17, x18, x19,x2, x20, x21, x22...
而我们的阅读习惯因该是这样的:
x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15, x16, x17...
如果是排列数字,按这种阅读习惯是理所当然的事情。可是对于字符串似乎就变得有些麻烦了,对于JScript脚本,系统提供了Array.sort()方法,可以高效的排列字符串。可是美中不足的是这个方法排序后的结果就是上面的第一种情况,完全不符合我们的阅读习惯:(。
于是我们考虑使用分段排序的方式解决这个问题,代码如下:
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由于使用了Array.sort()方法,排序效率非常高。10,000个字符串节点按阅读习惯排序所花的时间是281ms! 测试代码如下:
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后话:如果我们已知被排序的字符串是数字顺序的,那么用我们的SortStringArray()排序就行了,但是要去识别那些字符串是可以按数字顺序排列的,我想了想好像还很困难。看看下面这个xp的资源管理器的示例就清楚了:
红框里的文件的文件名就是没有数字顺序的,而xp的资源管理器就按普通的字符排序规则将其排序了。当然几十个百来个条目要判断出来还是很容易的,可是如果是好几千上万的条目,要找出有数字顺序的条目就比较的郁闷了。
本文转自博客园鸟食轩的博客,原文链接:http://www.cnblogs.com/birdshome/,如需转载请自行联系原博主。