Jq parsing get value

Question

I need to get some values ​​from a json file. I need to get an array (dimmer1, dimmer2)

Somebody knows?

{ "devices": { "dimmer1": { "protocol": ["kaku_dimmer"], "state": "off", "dimlevel": 1 }, "dimmer2": { "protocol": ["kaku_dimmer"], "state": "off", "dimlevel": 1 } } 

Answer 1

EDIT: After clarification in the comments, to retrieve the states of devices whose key begins with a "dimmer", use

 jq '[ .devices | to_entries[] | select(.key | startswith("dimmer")) | .value = .value.state ] | from_entries' filename.json 

Output:

 { "dimmer1": "off", "dimmer2": "off" } 

This works as follows:

• .devices selects the .devices attribute of a .devices object
• to_entries blows up an object into an array of key-value pairs describing its attributes (devices), which means that the attribute "foo": "bar" becomes the object { "key": "foo", "value": "bar" } , and the exploded object expands into an array of such objects (one for each attribute)
• to_entries[] unpacks this array to pass it through
• select(.key | startswith("dimmer")) , which selects devices whose key begins with dimmer
• .value = .value.state restructures a key-value pair describing the device, so that the value is replaced only by its state attribute
• [ all that ] does a JSON array of all this and
• [ all that ] | from_entries [ all that ] | from_entries converts an array of key-value pairs back to JSON objects.

The old answer (shortened), now obsolete, but perhaps interesting:

To get the device attribute keys in an array:

 jq '.devices | keys' filename.json 

To get the values ​​(also in the array),

 jq '[ .devices[] ]' filename.json 

I was not sure which of the two you had in mind.