PHP XPath 2.0 获得最大值，最大值

Question

I´ve a given XML structur:

<?xml version="1.0" encoding="utf-8"?>
<phonebooks>
    <phonebook name="xxx" owner="1">
        <contact>
            ...
            <mod_time>1452420868</mod_time>
            <uniqueid>2026447</uniqueid>
        </contact>
        <contact>
        ...
        </contact>
    </phonebook>
</phonebooks>

And I need the highest value (latest timestamp) from <mod_time>

xpathtester said, that max(//mod_time) will be allright.

So I tried in my script:

$modTime = $phonebook->xpath(max('//mod_time'));

which delivered me the warning

max(): When only one parameter is given, it must be an array

Any quick help around?

Thx

Answer 1

Just move the quotes to use the fn:max function and not the PHP function:

$modTime = $phonebook->xpath('max(//mod_time)');