Check existence of a node under a repeating node in XML using Xpath

user_2490252 0
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I have the following XML,

<Root>
  <Node>
    <Child>ch</Child>
    <Child>ch1</Child>
  </Node>

  <Node>
    <Child>ch2</Child>
    <Child>ch3</Child>
  </Node>

I want to check if all the nodes in the XML have at least one child node. If I use boolean(//Node/Child) it will check the whole XML and won't complain if any Node doesn't. have a Child node. If I use a predicate to mention the position, it works - boolean(//Node[1]/Child).

Thanks Sugata

xpath-2.0 xpath xml
2 Answers

It's possible by counting Nodes with a Child count equal to zero

not(count(//Node[count(Child) = 0]) > 0)

Given

<Root>
  <Node>
    <Child>ch</Child>
    <Child>ch1</Child>
  </Node>

  <Node>
    <Child>ch2</Child>
    <Child>ch3</Child>
  </Node>
  <Node/>
</Root>

Test failed, there are empty Node elements. In other words, the count of empty elements is greater than zero.

xmllint --xpath 'not(count(//Node[count(Child) = 0]) > 0)' test.xml; echo
false

Removing <Node/>

xmllint --xpath 'not(count(//Node[count(Child) = 0]) > 0)' test.xml; echo
true

If 2 empty node exist

xmllint --xpath 'count(//Node[count(Child) = 0])' test.xml; echo
2
user_28349780

A solid XPath-2.0 solution would be using a quantified expression like this:

every $x in /Root/Node satisfies count($x/*)

Here the fact is used that all values greater than zero for the count(...) function are interpreted as TRUE. Explicitly, it would be count($x/*) > 0.

user_13059690
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