Search by number of elements

[xxxserxxx]

Is there a search syntax that tests for the cardinality of a child array? Something like:

echo '{"item1": {"name": "foo", "children": []}, "item2": {"name": "bar", "children": [1,2]} | \
dasel '.(?: #.children > 0)'

would return the item2 object.

[TomWright]

This isn't a feature at the moment but I'd be happy to include it in the future.

I'll do some thinking and plan this out soon.

[xxxserxxx]

Hey, sorry -- I forgot to put REQ: in front of the subject. I was in a rush, and was sloppy.

[TomWright]

No worries at all!

I'm thinking of a syntax to select the length of an element so as it's part of the standard selector syntax - any suggestions?

[xxxserxxx]

Not really. I don't yet have a feel for the style of Dasel. Current array selectors are like .[5] for the 6th element, and .[] for the next index, so I'm inclined to suggest something with # -- probably because pound is so common in other languages. Maybe .[#] or #.[].

[TomWright]

I like the look of .[#], and will be able to re-use to select the length of maps and strings too.

I think I'll add that selector + the following comparisons when searching:

• >
• >=
• <
• <=

[xxxserxxx]

That would do it!

[TomWright]

@xxxserxxx This is now supported as of v1.14.0. I'll be releasing it shortly.

echo '{
  "item1": {
    "name": "foo",
    "children": []
  },
  "item2": {
    "name": "bar",
    "children": [
      1,
      2
    ]
  }
}' | dasel -p json -m '.(?:.children.[#]>0).name'

"bar"

Related docs are here:

• https://daseldocs.tomwright.me/selectors/length
• https://daseldocs.tomwright.me/selectors/dynamic

[xxxserxxx]

That's beautiful, thanks!