xpath to find max value in elements

[leegold2]

given:
<links>

<l><a>1</a><n>Building</n></l>

<l><a>4</a><n>Community</n></l>
<l><a>2</a><n>Comedy</n></l>

<l><a>3</a><n>Computer</n></l>

</links>

What is an Xpath statement to find the maximum value in the "a" element node. It would be 4. I have searched and tried many examples with no luck. It must be simple? I could easily parse into an array and use an array's max function but would like to learn the xpath way.

Also I have been trying to determine if I have Xpath 1.0 or 2.0 and have searched to find what I have. In python and PHP how do I determine what version I have?

Many examples are extremely long and complicated and I have not found one that works. Help appreciated. I am using libxml2 in Python 2.6.

Is there a way to get Xpath 2.0 from command line in Linux if I don't have it?

Thanks,

Lee G.

 

[leegold2]

I found it:

/links/l/a[not(. < /links/l/a)]