Iterate and concat using XPath EXpression

Question

hi everyone i have the following xml file

<author>
<firstname>Akhilesh</firstname>
<lastname>Singh</lastname>
</author>
<author>
<firstname>Prassana</firstname>
<lastname>Nagaraj</lastname>
</author>

and i am using the following jxpath expression

concat(author/firstName," ",author/lastName)

to get the value Akhilesh Singh ,Prassana Nagaraj but i am getting only Akhilesh Singh.My requirement is that i should get the value of both author by executing only one JXPath expression .Thanks in advance

Answer 1

concat() will return single string. If you want both results then you need to iterate over "author" element and do "concat(firstName," ",lastName)"

Answer 2

With XPath 1.0, when an argument type other than node set is expected, the first node in the node set is selected and then apply the type conversion (boolean type conversion is some how different).

So, your expresion (Note: no capital):

concat(author/firstname," ",author/lastname) 

It's the same as:

concat( string( (author/firstname)[1] ), " ", string( (author/lastname)[1] ) ) 

Depending on the host language you could use:

author/firstname|author/lastname

This is evaluate to a node set with firstName and lastName in document order, so then you could iterate over this node set extracting the string value.

In XPath 2.0 you could use:

string-join(author/concat(firstname,' ', lastname),' ,')

Output:

Akhilesh Singh ,Prassana Nagaraj

Note: Now, with sequence data type and function calls as steps, XPath resembles the functional language it claims to be. Higher Order Functions and partial applycation must wait to XPath 2.1 ...

Edit: Thanks to Dimitre's comments, I've corrected the string separator.

Answer 3

XPath 2.0 solution:

/*/author/concat(firstname, ' ', lastname, following-sibling::author/string(', '))