正则表达式中最短的比赛

Question

This is my regex:

/<strong>.*ingredients.*<\/ul>/im

Assuming the source code:

<strong>Contest closes on Thursday May 10th 2012 at 9pm PST</strong></div>
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* I am not affiliated with Blue Marble Brands or Ines Rosales Tortas in any way.&nbsp; I am not sponsored by them and did not receive any compensation to write this post...I just simply think the&nbsp;Tortas&nbsp;are wonderful!<br />
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<a href="http://1.bp.blogspot.com/-35J5vNrXkqE/T6htXTafrmI/AAAAAAAAA5E/g2mtiuSpSmw/s1600/food+003.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" mea="true" src="http://1.bp.blogspot.com/-35J5vNrXkqE/T6htXTafrmI/AAAAAAAAA5E/g2mtiuSpSmw/s640/food+003.JPG" width="640" /></a></div>
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<strong><span style="font-size: large;">Ingredients:</span></strong><br />
<ul>
<li>Ines Rosales Rosemary and Thyme Tortas</li>
<li>Pizza Sauce (ready made in a jar)</li>
<li>Roma Tomatoes</li>
<li>Roasted Red Peppers </li>
<li>Marinated Artichoke Hearts</li>
<li>Olives (I used Pitted Spanish Manzanilla Olives)</li>
<li>Daiya Vegan Mozzarella Cheese</li>
</ul>
<span style="font-size: large;"><strong>Directions:</strong></span><br />
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Spread small amount of pizza sauce over Torta. 

the Regex is greedy and grabs everything from <strong>Contest...</ul> but the shortest match should yield <strong><span style="font-size: large;">Ingredients...</ul>

this is my gist: https://gist.github.com/3660370

::EDIT:: Please allow flexibility inbetween strong tag and ingredients, and ingredients and ul.

Answer 1

Try this:

/<strong><span.*ingredients.*<\/ul>/im

Please refrain from regex-ing html. Use Nokogiri or a similar library instead.

Answer 2

This should work:

/(?!<strong>.*<strong>.*<\/ul>)<strong>.*?ingredients.*?<\/ul>/im

Test it here

Basically, the regex is using the negative lookahead to avoid multiple <strong> before <\\ul\u0026gt; like this: (?!<strong>.*<strong>.*<\\/ul>)

Answer 3

I think this is what you're looking for:

/<strong>(?:(?!<strong>).)*ingredients.*?<\/ul>/im

Replacing the first .* with (?:(?!<strong>).)* allows it to match anything except another <strong> tag before it finds ingredients . After that, the non-greedy .*? causes it to stop matching at the first instance of </ul> it sees. (Your sample only contains the one <UL> element, but I'm assuming the real data could have more.)

The usual warnings apply: there are many ways this regex can be fooled even in perfectly valid HTML, to say nothing of the dreck we usually see out there.