Checking for an element in an array with jsonpath_ng fails with JsonPathParseError

Question

I am trying to filter elements of my JSON data which contain specific values in an array with jsonpath_ng in Python. The data looks like

[
  {
    "id": "a",
    "test": [
      "a1",
      "a2"
    ]
  },
  {
    "id": "b",
    "test": [
      "a1",
      "a3"
    ]
  }
]

Testing the data in PyCharm with the query $[?(@.test contains "a2")] or $[?("a2" in @.test)] works just fine and returns the expected result

[
  {
    "id": "a",
    "test": [
      "a1",
      "a2"
    ]
  }
]

Trying this with jsonpath_ng in Python unfortunately results in an error...

from jsonpath_ng.ext import parse

a = [{"id": "a", "test": ["a1", "a2"]}, {"id": "b", "test": ["a1", "a3"]}]

jpexpr = parse('$[?(@.test contains "a2")]')

results in an error jsonpath_ng.exceptions.JsonPathParserError: Parse error at 1:11 near token contains (ID). Using jpexpr = parse('$[?("a2" in @.test)]') shows a similair behaviour jsonpath_ng.exceptions.JsonPathParserError: Parse error at 1:9 near token in (ID)

Neither with searching Google nor SO could I find an answer whether I'm doing something wrong of if there is a limitation in jsonpath_ng.

Is there just no support of this filter in jsonpath_ng? Does anyone have a great idea for a workaround if this was the case?

Thank you all for your assistance, .kai

Answer 1

jpexpr = parse('$[?(@..test[?(@ == "a2")].`len` > 0)]')

did the job for me...

from jsonpath_ng.ext import parse

a = [{"id": "a", "test": ["a1", "a2"]}, {"id": "b", "test": ["a1", "a3"]}]

jpexpr = parse('$[?(@..test[?(@ == "a2")].`len` > 0)]')

for i in jpexpr.find(a):
    print(i.value)

resulted in

{'id': 'a', 'test': ['a1', 'a2']}

exactly as I wanted.