XPath: Nodes that have a child node that have an attribute

Question

XML Fragment

    <component name='Stipulations'>
        <group name='NoStipulations' required='N'>
            <field name='StipulationType' required='N' />
            <field name='StipulationValue' required='N' />
        </group>
    </component>
    <component name='NestedParties3'>
        <group name='NoNested3PartyIDs' required='N'>
            <field name='Nested3PartyID' required='N' />
            <field name='Nested3PartyIDSource' required='N' />
            <field name='Nested3PartyRole' required='N' />
            <group name='NoNested3PartySubIDs' required='N'>
                <field name='Nested3PartySubID' required='N' />
                <field name='Nested3PartySubIDType' required='N' />
            </group>
        </group>
    </component>
    <component name='UnderlyingStipulations'>
        <group name='NoUnderlyingStips' required='N'>
            <field name='UnderlyingStipType' required='N' />
            <field name='UnderlyingStipValue' required='N' />
        </group>
    </component>

What I want is all "group" nodes which have a child node of type "field" and a name "StipulationType".

This is what I've tried so far:

dictionary.XPathSelectElements("group[field[@name='StipulationType']]")
dictionary.XPathSelectElements("group[./field[@name='StipulationType']]")

Good Question (+1). See my answer for a solution that often is more efficient than using //. :) — Dimitre Novatchev
– Dimitre Novatchev, Commented May 18, 2010 at 1:30

Jon W · Accepted Answer · 2010-05-18 01:09:33Z

2

Looks good. You might need to get a little more specific with your XPath depending on the implementation:

//group[field[@name='StipulationType']]

or

/component/group[field[@name='StipulationType']]

should work

answered May 18, 2010 at 1:09

Jon W

15.9k6 gold badges39 silver badges48 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Jonathan Allen Over a year ago

I see what I did wrong. I didn't include the // in front of group, which is vital given my source xml. (My sample doesn't indicate how random the nesting levels truly are.)

Jon W Over a year ago

ah. Yes, when it doubt use the // to search at all levels, but bear in mind the performance penalty this can cause.

Dimitre Novatchev · Accepted Answer · 2010-05-18 01:30:12Z

The problem:

dictionary.XPathSelectElements("group[field[@name='StipulationType']]")

This selects all the group elements satisfying the predicate, which are children of the current node.

However, you want all group elements (satisfying the predicate) -- from the XML fragment it is clearly seen that not all group elements have the same parent.

The solution:

Evaluate the XPath expression from the grand-grandparent (based on the provided fragment!):

One example would be:

component/group[field[@name='StipulationType']]

Based on the structure of the complete document (not provided), more location steps might be necessary.

What to avoid:

Avoid the // abbreviation as it may cause (with not good optimizing XPath engines) an extensive traversal of the whole subtree (even document) that starts from the node against this is evaluated.

Collectives™ on Stack Overflow

XPath: Nodes that have a child node that have an attribute

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related