How to extract "$" by jsonpath?

Question

I'd like to extract an elememt by "$". But it retrieves nothing (the 1st call of main.py). Does anybody know what is wrong? Thanks.

$ cat data.json
{
  "id": {
    "$": {
      "view": "all",
      "id": "sec4",
      "role": "materials-methods"
    }
  }
}

$ cat main.py 
#!/usr/bin/env python
# vim: set noexpandtab tabstop=2 shiftwidth=2 softtabstop=-1 fileencoding=utf-8:

import sys
import json
json_data = json.load(sys.stdin)
import jsonpath_rw_ext
res = jsonpath_rw_ext.match(sys.argv[1], json_data)
for match in res:
    print match.keys()

$ < data.json ./main.py '$."$"'
$ < data.json ./main.py '$."id"'
[u'$']

I hope you agree with my edit. It makes it simpler to create the test setup than using a here-doc (which couldn't be copy/pasted because of the `> ` in front). If you disagree, feel free to roll it back. Why do you use Python2? — hek2mgl, Aug 13 '19 at 23:53
Looks fine. I just have been using python 2 for all my code. It takes time to change. — user1424739, Aug 13 '19 at 23:55

score 0 · Answer 1 · answered Aug 14 '19 at 00:13

0

The right jsonpath expression to use would be '$.id.$'.

Note: Please don't use Python2 for new code and migrate existing Python2 code to Python3

answered Aug 14 '19 at 00:13

hek2mgl

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I don't want to specify `id`. I want to search for any nodes of `$`, which does not have to be a child of `id`. – user1424739 Aug 14 '19 at 01:01
The expressions says: Return all child nodes from `$`. – hek2mgl Aug 14 '19 at 07:03
I think the jsonpath expression should be `$.."$"`. BTW, I'd like to and I'd like to add the restriction that there is a "role" field with the value "materials-methods", and I'd like to get the parent of the node found. How to do it? – user1424739 Aug 14 '19 at 10:34
Ok, you want to extract information from an element `$`, regardless of it's position in the tree. Your question doesn't say that. To summarize it, you want to retrieve the parent node of a role node which's value is xyz, regardless of it's position in the tree. Is that what you want? – hek2mgl Aug 14 '19 at 10:43
Not precisely. I'd like to retrieve the parent of a node who has a field "role" with a value "xyz". The position of the node in the tree does not matter. – user1424739 Aug 14 '19 at 10:48

score 0 · Answer 2 · answered Sep 02 '19 at 18:01

0

Try this one

$[?(!@.$)]

This ignores all the nodes containing $

answered Sep 02 '19 at 18:01

kaushik

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How to extract "$" by jsonpath?

2 Answers2