preg_match and preg_replace question

Question

I am creating dynamic XML and need to update the lastBuildDate in a file on my server. I know how to do everything but change that.

I figured I could use preg_match to look for the expression and preg_replace to replace it. My string will look like this:

$build_date = '<lastBuildDate>Fri 16 Sep 2011 2:30:15 -6:00 GMT<lastBuildDate>';

How do I use preg_match to find the date inside the tags and then how do I replace it? I'm a noob when it comes to regular expressions, which is what I think I have to use. I'm just not sure how to find a wildcard inside that string.

Thanks.

Don't parse XML or HTML with regex: http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags Instead, use an XML parser: http://stackoverflow.com/questions/3577641/best-methods-to-parse-html-with-php — , Sep 16 '11 at 21:34
I didn't know that. I didn't realize there was so much involved. OK, I'll use an XML parser. Thanks. — sehummel, Sep 16 '11 at 21:39
on the other hand it's helpful practice for a regex newbie to practice writing regex to parse tag's — ina, Sep 16 '11 at 21:44

score 1 · Answer 1 · answered Sep 16 '11 at 21:36

1

What I advise you to do is read the preg_match and PCRE syntax documentation, then use a tool such as RegExr which will explain the regex you are writing with English words. It's a great tool to begin with.

answered Sep 16 '11 at 21:36

JRL

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http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags/1732454#1732454 – Sep 16 '11 at 21:43
2

@downvoter: what if the data is not XML or HTML, but just a snippet in a file? The advice don't use regex to parse XML or HTML is great advice, but that doesn't mean it can be applied to any and all situations. Stop downvoting posts based on religious "omg don't use that it's evil" tirades. I didn't advocate specificaly using a regex in this case, I gave advice on how to learn to use a regex. Jeez.... – JRL Sep 16 '11 at 21:58

score 0 · Answer 2 · answered Sep 16 '11 at 21:46

At first glance I think you're missing a '/' on your close tag. I'll assume there is supposed to be one.

Like what others have already commented, you should be using an XML parser.

But, to answer how to do this w/ preg_replace, you could do this:

$build_date = "<lastBuildDate>Fri 16 Sep 2011 2:30:15 -6:00 GMT</lastBuildDate>";

function replacer($matched) {
    return "<lastBuildDate>" . strrev($matched) . "</lastBuildDate>";
}

echo preg_replace("/<lastBuildDate>(.*?)<\/lastBuildDate>/me", "replacer('$1')", $build_date);

This will echo the xml tag, where (for the sake of example) the date string is simply reversed. Again, I'd advise against using an expression to do this.

preg_match and preg_replace question

2 Answers2