Jq: How to dump paths to leafs and the leaf values?

[tischwa]

Hi,

I'm trying to achieve the following: Dump paths to leafs and the leaf values.

Example:

$ echo '{"a":{"b":1,"c":2},"d":["x",1]}' | jq ''
a.b = 1
a.c = 2
d.0 = x
d.1 = 1

I think using the recurse-function it should be possible somehow, any ideas?

It is a bit similar to what

https://github.com/wuyongzheng/json-liner

does, but the output format is more or less fixed there. And using jq I could apply all of jq's filtering possibilities.

Regards,
Tilo

[ghost]

def r(p):.as$in| if .>=[] then keys[]| .as$k| $in[.]| r(p+".\($k)") else p+" = \(.)" end; r("")

[tischwa]

Nice!

[nicowilliams]

This needs magic though. That expression, and simplified versions, are too cumbersome. I opened #97 which I see now is a dup of this one :(

[stedolan]

Here's a not-too-magical version. First you define a function to get all of the leaves of the structure:

def leaves: if type == "array" or type == "object" then .[] | leaves else . end;

Then, you can ask jq for all of the paths that this function traverses:

path(leaves)

The output is:

["d",0]
["d",1]
["a","c"]
["a","b"]

You can use getpath to retrieve the value at a particular path:

path(leaves) as $p | [$p, getpath($p)]

produces:

[["d",0],"x"]
[["d",1],1]
[["a","c"],2]
[["a","b"],1]

Converting these into a readable non-JSON format is still a bit of a pain since jq's string manipulation is weak, but that's a separate issue.

[ghost]

Why does it need $p? i.e. this doesn't work: path(leaves) | [., getpath(.)]

[stedolan]

You're calling getpath passing the path as input. getpath expects the object to inspect as input and the path as the first argument.

[ghost]

Thanks; my silly error.

[lucaswerkmeister]

You can also use paths(scalars) instead of path(leaves) to get a version without custom functions:

paths(scalars) as $p | [$p, getpath($p)]

As far as I can tell, it’s equivalent to @stedolan’s suggestion.

[tlwhitec]

Hi, maybe it's silly to ask on such an old issue, but is there a reason getpath is not documented?

[pkoppstein]

getpath is documented in the manual at
https://stedolan.github.io/jq/manual/

it was not documented in earlier versions, perhaps because it was originally viewed as being subject to change.