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phpxmldomdomxpath

DOMXPath get sibling depending on previous sibling value

Let's say I have this:

<foo>
    <bar>CCC</bar>
    <baz>sometexthere</baz>
</foo>
<foo>
    <bar>AAA</bar>
    <baz>sometext</baz>
</foo>
<foo>
    <bar>DDD</bar>
    <baz>something</baz>
</foo>

Now, I want to get the baz value, which is coming right after bar with the value AAA (!but only with the value AAA!). I don't know how many "foo"s I have, so I can't exactly write something like:

$element->item(0) // I don't know the exact number

So how can I get the value of the baz, which follows after bar with a particular value?

(For the example above, I would like to get sometext because it comes after AAA)

Solution

  • A basic query would be to find the bars that contain AAA, then navigate to the corresponding baz element.

    //foo/bar[.="AAA"]/../baz

    Or, find all baz and filter based on the associated bar.

    //foo/baz[../bar = "AAA"]

    Or, bazs within foos containing bar having AAA.

    //foo[bar="AAA"]/baz

    If you're not familiar with XPath expressions, bookmark XML Path Language (XPath) for later.