CODEWITHSUNDEEP
jsonxpathmarklogic
Fan Li
Fan Li

Reputation: 1077

MarkLogic XPath on JSON with "@" symbol in property name

I am dealing with some JSON-LD data in MarkLogic and have trouble using XPath on property names with "@" symbol. For example:

{
  "@type": "News",
  "title": "some title",
  "description": "some description"
}

My goal is to retrieve the title if the type is "News". I understand "@" is reserved to represent attribute in XPath, so something below should not work.

doc.xpath('.[@type="News"]/title')

With the xdmp.encodeForNCName function, I see the "@" symbol is represented as _40_ in the JSON representation. But it still doesn't work.

doc.xpath('.[_40_type="News"]/title')

Upvotes: 2

Views: 319

Answers (3)

grtjn
grtjn

Reputation: 20414

While using fn:name() would work too, as suggested by the other answers, you can address nodes with funny spelling in MarkLogic XPath directly too. Probably a deviation from the official XPath standard itself, but MarkLogic allows writing expressions like:

doc.xpath('node("@type")[. eq "News"]/title'

Very useful for JSON properties containing spaces and such as well..

HTH!

Upvotes: 2

supputuri
supputuri

Reputation: 14135

Here is the dirty solution.

 .[@*[name() = '@type']][@*='News']/title

I know you are working with json, but I just checked the xpath in html with similar attribute and value combination. You can see the xpath considered both attribute name and value (as it's not selecting other node with the same name but different value).

enter image description here

Upvotes: 0

Mads Hansen
Mads Hansen

Reputation: 66783

You could test the name() in a predicate:

doc.xpath('.[*[contains(name(), "@type")] = "News"]/title')

Upvotes: 1

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