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XPath to select Element by attribute value

I have following XML.

<?xml version="1.0" encoding="UTF-8"?>
<Employees>
    <Employee id="3">
        <age>40</age>
        <name>Tom</name>
        <gender>Male</gender>
        <role>Manager</role>
    </Employee>
    <Employee id="4">
        <age>25</age>
        <name>Meghna</name>
        <gender>Female</gender>
        <role>Manager</role>
    </Employee>
</Employees>

I want to select Employee element with id="4".

I am using below XPath expression which is not returning anything.

//Employee/[@id='4']/text()

I checked it at http://chris.photobooks.com/xml/default.htm and it says invalid xpath, not sure where is the issue.


J
JLRishe

You need to remove the / before the [. Predicates (the parts in [..]) shouldn't have slashes immediately before them - they go directly after the node selector they are associated with.

Also, to select the Employee element itself, you should leave off the /text() at the end. Otherwise you'd just be selecting the whitespace text values immediately under the Employee element.

//Employee[@id = '4']

One more thing to note: // can be very slow because it searches the entire document for matching nodes. If the structure of the documents you're working with is going to be consistent, you are probably best off using a more explicit path, for example:

/Employees/Employee[@id = '4']

Note that // selects and searches over all nodes of the document which can be slow. Instead, if the structure of the document is known then use a proper path, like suggested in Gilles' answer below.
@Jens Yes, that's absolutely true. I've edited my answer to add an addendum.
d
de-russification

As a follow on, you could select "all nodes with a particular attribute" like this:

//*[@id='4']

G
Gilles Quenot

Try doing this :

/Employees/Employee[@id=4]/*/text()

does xmllint loads the whole xml file into memory before looking for the ids?. I have a xml file of 46 GB and I am looking for ids in it
xml file of 46 GB - there is the problem.