I appreciate the help, and I'm sorry for such a general question. One thing to make clear is that the ignore_first and ignore_last characters are subsets of wordchars. The point of those settings is to allow characters within a word, but not at the start/end. The classic example is that a dot is ok within a host name, but not at the end (e.g. at the end of a sentence).

The other thing that complicates this a bit is I'm not showing all the original text with the words highlighted in the final output, but rather just a few words on either side of the highlighted text. Like a google search shows. Thus, I also need to be careful not to print words twice when highlighted words are close together.

That is the reason I split the source text into an array of "swish" words and non swish words -- so I could easily mark words on either side of the matched word.

@words = split /([^$wordchars])/, $source_text;<p>

[download]

I use two arrays to track this now (instead of an array of arrays) as it was faster to avoid all the dereferencing.

Here's a specific question: The "problem" with the above code is that I still need to remove the leading and trailing ignore characters. So, that's an extra pattern match for every word - one time for the split, and then another to extract out a word from its ignore chars.

I tried to find an expression to use in the above spilt that would do this in one shot, but it was looking like a complicated expression that might be slower than doing two matches. But I never found a pattern that I could test.

I also wonder if using a repeating pattern with /g might be faster than my word-by-word checking. But then I'm back to the problem of how to print the words around the match.

Thanks again for your help.

In reply to Re: Re: Optimizing regular expressions by moseley
in thread Optimizing regular expressions by moseley

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