Dave's Brain

Browse - programming tips - perl use non greedy matches to quickly parse xml

Date: 2010jun29
Language: perl

Q.  What is the best way to parse XML or HTML?

A.  Use non-greedy matches.   And the s g options.

For example, if you have a RSS feed which is XML with
multiple <item>'s.  Do this:

	@a = $content =~ m|\<item\>(.*?)\</item\>|sg;

	for $i (@a)
	{
		print "item=$i\n";
	}

Here is what's happening:

We use | to delimit the match so we don't have to escape the /

The .* matches any character(s).  Adding the ? makes it non-greedy
so we get each <item> at a time.  Because <item> is any characters.

The s option folds several lines together.  So this works
if there are newlines.

The g option gets all (global) matches.

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