How to recursively delete all keys that match a given pattern?
I have following jq config, but it doesn't seem to work:
walk( if (type == "object" and (.[] | test('.*'))) then del(.) else . end)
A robust way (with respect to different jq versions) to delete all keys matching a pattern (say PATTERN) would be to use the idiom:
with_entries(select( .key | test(PATTERN) | not))
Plugging this into walk/1 yields:
walk(if type == "object" then with_entries(select(.key | test(PATTERN) | not)) else . end)
Related
This question already has answers here:
Using jq how can I replace the name of a key with something else
(2 answers)
Closed 4 months ago.
jq key assignment is not working.
I tried what was here for my use case.
Using jq how can I replace the name of a key with something else
in this case I want to change id to item_id`.
jq '.item[] | select(.closed == false) | select(.id == "1234") | .["id"] = .["item_id"] | .' data.json | less
the result does not error but "id" gets a value of null and there is not key called item_id. so there is something I am not getting right about assignment of the key.
You can just delete the old field using del, and add another one using object construction:
jq '.item[] | select(.closed == false and .id == "1234") | del(.id) + {item_id: .id}' data.json
Or use with_entries to "rename" the old field:
jq '.item[] | select(.closed == false and .id == "1234") | with_entries(select(.key == "id").key = "item_id")' data.json
I have a JSON with dynamic data and not sure how I can retrieve data with JQ.
My JSON is:
{
"RuntimeSources":{
"env-name-DYNAMIC":{
"the-dynamic-value-i-need-to-get":{
"url":""
}
}
},
"DeploymentId":147,
"Serial":158
}
'env-name-DYNAMIC' is dynamic and 'the-dynamic-value-i-need-to-get' is the same.
The json structure is always the same. How can I get 'the-dynamic-value-i-need-to-get'? Also I may need to retrieve 'env-name-DYNAMIC'
Use the keys[] attribute
.RuntimeSources | keys[]
and also
.RuntimeSources | keys[] as $k | .[$k] | keys[]
Since you had also mentioned, the structure doesn't change, you can just select the paths that contains 3 levels
paths | select( length == 3 ) | .[1]
paths | select( length == 3 ) | .[2]
I managed to get it with:
jq '.RuntimeSources | .[] | keys'
Not sure if it's the best solution, but did the trick.
I've encountered some difference between null and nothing, can somebody explain it? As in most languages null is considered/used to represent nothing.
The select is documented to return no output. And adding(ie. +) null to X yields X. Now consider these demonstrative examples(takes no input):
adding nothing
here we have empty object, which we update with nothing:
{} | . |= . + ({} | select (.foo == 123))
which results in
null
adding null
same template but with alternative operator to substitute nothing to null:
{} | . |= . + ({} | select (.foo == 123)//null)
which results in
{}
Can someone explain the difference nothing vs null?
null is just a regular JSON value; and conceptually, it is totally different from the absence of a value, i.e, what you termed nothing. Take a look at these for example (empty is a filter that returns nothing):
$ jq -n '[null] | length'
1
$ jq -n '[empty] | length'
0
That {} + null returns {} back, and that {} | . |= empty does exactly what del(.) does are merely design choices.
Hello i managed to create this jq filter .profiles | recurse | .gameDir? | if type == "null" then "" else . end | scan("{REPLACE}.*") | sub("{REPLACE}"; "{REPLACESTRINGHERE}"). it succesfully replaces what i want (checked at jqplay.org) but now i'd like to print the full json and not just the modified strings
Adapting your query:
.profiles |= walk( if type == "object" and has("gameDir")
then .gameDir |=
(if type == "null" then "" else . end
| scan("{REPLACE}.*") | sub("{REPLACE}"; "{REPLACESTRINGHERE}"))
else .
end )
(This can easily be tweaked for greater efficiency.)
If your jq does not have walk, you can google it (jq “def walk”) or snarf its def from the jq FAQ https://github.com/stedolan/jq/wiki/FAQ
walk-free approach
For the record, here's an illustration of a walk-free approach using paths. The following also makes some changes in the computation of the replacement string -- notably it eliminates the use of scan -- so it is not logically equivalent, but is likely to be more useful as well as more efficient.
.profiles |=
( . as $in
| reduce (paths | select(.[-1] == "gameDir")) as $path ($in;
($in | getpath($path)
| if type == "null" then ""
else sub(".*{REPLACE}"; "{REPLACESTRINGHERE}")
end) as $value
| setpath($path; $value) ))
Say we have the following JSON:
[
{
"dir-1": [
"file-1.1",
"file-1.2"
]
},
"dir-1",
{
"dir-2": [
"file-2.1"
]
}
]
And we want to get the next output:
"dir-1/file-1.1"
"dir-1/file-1.2"
"dir-1"
"dir-2/file-2.1"
i.e. to get the paths to all leafs, joining items with /. Is there a way to do that on JQ?
I tried something like this:
cat source-file | jq 'path(..) | [ .[] | tostring ] | join("/")'
But it doesn't produce what I need even close.
You could take advantage of how streams work by merging the path with their values. Streams will only emit path, value pairs for leaf values. Just ignore the numbered indices.
$ jq --stream '
select(length == 2) | [(.[0][] | select(strings)), .[1]] | join("/")
' source-file
returns:
"dir-1/file-1.1"
"dir-1/file-1.2"
"dir-1"
"dir-2/file-2.1"
Here is a solution similar to Jeff Mercado's which uses tostream and flatten
tostream | select(length==2) | .[0] |= map(strings) | flatten | join("/")
Try it online at jqplay.org
Another way is to use a recursive function to walk the input such as
def slashpaths($p):
def concat($p;$k): if $p=="" then $k else "\($p)/\($k)" end;
if type=="array" then .[] | slashpaths($p)
elif type=="object" then
keys_unsorted[] as $k
| .[$k] | slashpaths(concat($p;$k))
else concat($p;.) end;
slashpaths("")
Try it online at tio.run!
Using --stream is good but the following is perhaps less esoteric:
paths(scalars) as $p
| getpath($p) as $v
| ($p | map(strings) + [$v])
| join("/")
(If using jq 1.4 or earlier, and if any of the leaves might be numeric or boolean or null, then [$v] above should be replaced by [$v|tostring].)
Whether the result should be regarded as "paths to leaves" is another matter...