How do I access certain elements with jmespath using slicing?

Question

I have the following JSON

{
    "items": [
        {
            "configurationStatus": "SYNCED",
            "conflictDetectionState": "IN_SYNC",
            "connectivityState": "ONLINE",

I can access individual elements inside with items[*].isModel, but, I cannot figure out how to access the first 3 elements. I tried something like this items[*].[0:2], but it didn't work. I am curious how to access the first 3 elements using slicing.

Answer 1

You would possibly face some issue trying to achieve this because, as pointed in the JMESPath documentation, object are:

object (an unordered collection of key value pairs)

^{Source: https://jmespath.org/specification.html, emphasis, mine}

So you might end up with different keys based on the implementation and have really random results.

---

Now the issue with your approach is that slices can only act on arrays.

A slice expression allows you to select a contiguous subset of an array.

^{Source: https://jmespath.org/specification.html#slices, emphasis, mine}

What you could do then, in order to have an array out of a hash is to use the values function, but mind that you'll lose the key/value association in the process.
Then, given you have an array, you can now apply the slicing technique.

So with the query:

items[].values(@)[0:3]

On the JSON:

{
    "items": [
        {
            "configurationStatus": "SYNCED",
            "conflictDetectionState": "IN_SYNC",
            "connectivityState": "ONLINE",
            "foo": "bar",
            "baz": "qux"
        },
        {
            "configurationStatus": "SYNCED′",
            "conflictDetectionState": "IN_SYNC′",
            "connectivityState": "ONLINE′",
            "foo": "bar′",
            "baz": "qux′"
        }
    ]
}

This would give:

[
  [
    "SYNCED",
    "IN_SYNC",
    "ONLINE"
  ],
  [
    "SYNCED′",
    "IN_SYNC′",
    "ONLINE′"
  ]
]