Get nodes where child node contains an attribute

Question

Suppose I have the following XML      lt book category  CLASSICS  gt     lt title lang  it  gt Purgatorio lt  title gt     lt author gt Dante Alighieri lt  author gt     lt year gt 1308 lt  year gt     lt price gt 30 00 lt  price gt   lt  book gt    lt book category  CLASSICS  gt     lt title lang  it  gt Inferno lt  title gt     lt author gt Dante Alighieri lt  author gt     lt year gt 1308 lt  year gt     lt price gt 30 00 lt  price gt   lt  book gt    lt book category  CHILDREN  gt     lt title lang  en  gt Harry Potter lt  title gt     lt author gt J K  Rowling lt  author gt     lt year gt 2005 lt  year gt     lt price gt 29 99 lt  price gt   lt  book gt    lt book category  WEB  gt     lt title lang  en  gt XQuery Kick Start lt  title gt     lt author gt James McGovern lt  author gt     lt author gt Per Bothner lt  author gt     lt author gt Kurt Cagle lt  author gt     lt author gt James Linn lt  author gt     lt author gt Vaidyanathan Nagarajan lt  author gt     lt year gt 2003 lt  year gt     lt price gt 49 99 lt  price gt   lt  book gt    lt book category  WEB  gt     lt title lang  en  gt Learning XML lt  title gt     lt author gt Erik T  Ray lt  author gt     lt year gt 2003 lt  year gt     lt price gt 39 95 lt  price gt   lt  book gt    I would like to do an xpath that gets back all book nodes that have a title node with a language attribute of  it     My attempt looked something like this     book title  lang  it     But that didn t work  I expect to get back the nodes      lt book category  CLASSICS  gt     lt title lang  it  gt Purgatorio lt  title gt     lt author gt Dante Alighieri lt  author gt     lt year gt 1308 lt  year gt     lt price gt 30 00 lt  price gt   lt  book gt    lt book category  CLASSICS  gt     lt title lang  it  gt Inferno lt  title gt     lt author gt Dante Alighieri lt  author gt     lt year gt 1308 lt  year gt     lt price gt 30 00 lt  price gt   lt  book gt    Any hints

User · Answer

I would think your own suggestion is correct  however the xml is not quite valid  If you are running the   book title  lang  it    on  lt root gt  Your XML Here  lt  root gt  then the free online xPath testers such as one here will find the expected result

User · Answer

Try    book title  lang    it     This reads    get all book elements   that have at least one title   which has an attribute lang   with a value of  it       You may find this helpful     it s an article entitled  XPath in Five Paragraphs  by Ronald Bourret   But in all honesty    book title  lang  it    and the above should be equivalent  unless your XPath engine has  issues   So it could be something in the code or sample XML that you re not showing us -- for example  your sample is an XML fragment  Could it be that the root element has a namespace  and you aren t counting for that in your query  And you only told us that it didn t work  but you didn t tell us what results you did get

User · Answer

Try to use this xPath expression     book title  lang  it        That should give you all book nodes in  it  lang

User · Answer

Years later  but a useful option would be to utilize XPath Axes  https   www w3schools com xml xpath axes asp   More specifically  you are looking to use the descendants axes   I believe this example would do the trick     book descendant  title  lang  it      This allows you to select all book elements that contain a child title element  regardless of how deep it is nested  containing language attribute value equal to  it    I cannot say for sure whether or not this answer is relevant to the year 2009 as I am not 100  certain that the XPath Axes existed at that time  What I can confirm is that they do exist today and I have found them to be extremely useful in XPath navigation and I am sure you will as well

User · Answer

book title  lang  it      is actually equivalent to      book title  lang    it     I tried it using vtd-xml  both expressions spit out the same result    what xpath processing engine did you use  I guess it has conformance issue Below is the code  import com ximpleware    public class test1     public static void main String   s  throws Exception        VTDGen vg   new VTDGen          if  vg parseFile  c  books xml   true              VTDNav vn   vg getNav              AutoPilot ap   new AutoPilot vn             ap selectXPath    book title  lang  it                           ap selectXPath    book title  lang  it                 int i            while  i ap evalXPath     -1                 System out println  index    gt   i                           if  vn endsWith i    lt  test                  System out println   good                  else               System out println   bad

[xml] Get nodes where child node contains an attribute

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