Add documentation on how to update and remove nodes

[KaiRoesner]

The package documentation says it provides "the ability to update or removes nodes in the tree" but doesn't specify how this is done. Please add this to the documentation!

[1wang-wood]

use parse('exp').update(data, value)

[KaiRoesner]

What about removing nodes? Are there more useful functions that can be applied to a parsed JSONPath expression? Please add the info to the README!

[ec-agmednet]

I agree, been trying to find out how to remove elements in a list. I don't see any documentation from this project or the two it merged from. Looking at the code and PRs there is this open one for delete: https://github.com/h2non/jsonpath-ng/pull/43/

There is a comment saying it is the same as filter but it looks different to me, mutating the json with a del. @h2non any help would be much appreciated!

[ec-agmednet]

@KaiRoesner I was able to do this manually for a list of elements I wanted to remove data with a disabled=True flag from:

    import json
    from jsonpath_ng.ext import parse
    json_dict = {"l": [{"e": 1}, {"e": 2, "disabled": True}, {"e": 3}]}
    jp = parse('$..*[?(@.disabled = true)]')
    for path in jp.find(json_dict):
        # import pdb; pdb.set_trace()
        if path.value:
            index = path.path.index
            print(f'{path.context.full_path=} {index=} BEFORE:\n{json.dumps(json_dict, indent=2)}\n')
            del path.context.value[index]
            print(f'AFTER:\n{json.dumps(json_dict, indent=2)}\n')

hope this helps, similar could probably be done for dict keys...

[gh-andre]

Updated documentation or at least a few examples on how to manipulate dictionaries would be helpful indeed. Type hints would also go a long way as well.

After wading through the code, seems that the intended way to delete fields is via a callback. At least I couldn't find any alternative. Maybe I missed something.

doc = {"a": 1, "b": "X"}

c_jp = jsonpath_ng.parse("$.c")

c_jp.update_or_create(doc, 123)

print(doc)      # {'a': 1, 'b': 'X', 'c': 123}

c_jp.update(doc, 456)

print(doc)      # {'a': 1, 'b': 'X', 'c': 456}

def rm_field(value: Any, mydoc: Dict[str, Any], name: str) -> None:
    del mydoc[name]

c_jp.update(doc, rm_field)

print(doc)      # {'a': 1, 'b': 'X'}

[KaiRoesner]

Relates to #44 and #106 Fixed with commit #f5e8987