Does xpath query has Limit option like mysql

I want to limit number of result I receive from xpath query.

For example:-

$info = $xml->xpath("//*[firstname='Sheila'] **LIMIT 0,100**");

You see that LIMIT 0,100.

回答1:

You should be able to use "//*[firstname='Sheila' and position() <= 100]"

Edit:

Given the following XML:

<root> 
    <country.php desc="country.php" language="fr|pt|en|in" editable="Yes"> 
        <en/> 
        <in> 
            <cityList desc="cityList" language="in" editable="Yes" type="Array" index="No"> 
                <element0>Abu</element0>
                <element1>Agartala</element1>
                <element2>Agra</element2> 
                <element3>Ahmedabad</element3>
                <element4> Ahmednagar</element4> 
                <element5>Aizwal</element5>
                <element150>abcd</element150> 
            </cityList> 
        </in> 
    </country.php> 
</root>

You can use the following XPath to get the first three cities:

//cityList/*[position()<=3]

Results:

Node    element0    Abu
Node    element1    Agartala
Node    element2    Agra

If you want to limit this to nodes that start with element:

//cityList/*[substring(name(), 1, 7) = 'element' and position()<=3]

Note that this latter example works because you're selecting all the child nodes of cityList, so in this case Position() works to limit the results as expected. If there was a mix of other node names under the cityList node, you'd get undesirable results.
For example, changing the XML as follows:

<root> 
    <country.php desc="country.php" language="fr|pt|en|in" editable="Yes"> 
        <en/> 
        <in> 
            <cityList desc="cityList" language="in" editable="Yes" type="Array" index="No"> 
                <element0>Abu</element0>
                <dog>Agartala</dog>
                <cat>Agra</cat> 
                <element3>Ahmedabad</element3>
                <element4> Ahmednagar</element4> 
                <element5>Aizwal</element5>
                <element150>abcd</element150> 
            </cityList> 
        </in> 
    </country.php> 
</root>

and using the above XPath expression, we now get

Node    element0    Abu

Note that we're losing the second and third results, because the position() function is evaluating at a higher order of precedence - the same as requesting "give me the first three nodes, now out of those give me all the nodes that start with 'element'".

回答2:

Ran into the same issue myself and had some issue with Geoffs answer as it, as he clearly describes, limits the number of elements returned before it performs the other parts of the query due to precedence.

My solution is to add the position() < 10 as an additional conditional after my other conditions have been applied e.g.:

//ElementsIWant[./ChildElementToFilterOn='ValueToSearchFor'][position() <= 10]/.

Notice that I'm using two separate conditional blocks. This will first filter out elements that live up to my condition and secondly only take 10 of those.