I am trying to update a json file using jq. My json file looks like
{
"A": "123",
"B": "456",
"C": "789",
"D": []
}
Here the value for key D is empty so I am adding some values to it. And this is working
Now, if for some reason the key doesn't exist then I need to first create the key D. And I am not able to achieve this
{
"A": "123",
"B": "456",
"C": "789",
}
cat test.json | jq 'has("D")' = false && cat test.json jq --argjson addobj '{"D": "[]"}'
I am getting the error
jq: error: Could not open file =: No such file or directory
jq: error: Could not open file false: No such file or directory
expected output
{
"A": "123",
"B": "456",
"C": "789",
"D": []
}
Can anyone please let me know what is the issue here and how to resolve it?
Thanks in advance.
P.S: Please let me know if any info is missing here
Your problem is not (only) with jq, but with shell syntax.
But if all you are trying to do is to update the value of key D whether it exists or not, then you don't need any checks and can simply assign the new value:
$ jq '.D = ["new value"]' test.json
{
"A": "123",
"B": "456",
"C": "789",
"D": [
"new value"
]
}
If you want to modify the current value, the operator |= might be helpful.
An alternative, equivalent program would be '. + { D: ["new value"] }'
If you really want to fix your script, here's a working version of it:
if jq -e 'has("D")' test.json >/dev/null; then
# key exists
jq --argjson addobj '{"D": "[]"}' 'your program here' test.json
else
# key doesn't exist
jq 'your other program here'
fi
But this is arguably easier in jq directly:
jq --argjson addobj '{"D": "[]"}' '
if has("D") then
# D exists
. # <- your jq program
else
# D doesn't exist
. # <- your other jq program
end
' test.json
If your goal is to simply insert the key with a default value if it doesn't exist, but keep any existing value, the following simple jq program (and nothing else) should take care of that:
jq '{D: []} + .' test.json
(keys in the RHS overwrite keys from the LHS – {a:1}+{a:2} becomes {a:2})
Objects in JavaScript (and by extension JSON), are a bag of unordered key-value pairs and {a:1,b:2} is the same object as {b:2,a:1}.
However, jq mostly keeps order of keys (although I don't think this is specified/guaranteed). So, a slightly more complicated version which puts D at the end of the object, but keeps existing values would be:
jq '.D |= (. // [])' test.json
My input JSON is of the format:
{
"a": "apple",
"b": "banana",
"c": 5,
"d": ["this", "is", "an", "array"],
"e": false
}
What I want is:
a="apple"
b="banana"
c=5
d=["this", "is", "an", "array"]
e=false
Note that only strings in the input JSON have quotes in the output.
By using jq -r 'to_entries[] | "\(.key)=\"\(.value)\""' I could generate an output like
a="apple"
b="banana"
c="5"
d="["this", "is", "an", "array"]"
e="false"
So my question is:
Is using jq the right way to approach this problem? Or should I use regex?
If jq is the correct direction, how do I fix what I've come up with?
You can test whether .value is a string or not using type (manual entry).
jq -r 'to_entries[]
| "\(.key) = \( .value
| if type == "string"
then "\"\(.)\""
else .
end
)"'
I use jq 1.6 in a Windows 10 PowerShell enviroment and trying to select keys from coincidentally numeric json objects.
Json exampel:
{
"alliances_info":{
"744085325458334213":{
"emblem":3,
"name":"wellwell",
"member_count":1,
"level":1,
"military_might":1035,
"public":false,
"tag":"MELL",
"slogan":"",
"id":744085325458334213
},
"744128593839677958":{
"emblem":0,
"name":"Brave",
"member_count":1,
"level":1,
"military_might":1035,
"public":false,
"tag":"GABA",
"slogan":"",
"id":744128593839677958
},
"746034084459209223":{
"emblem":0,
"name":"Queen",
"member_count":1,
"level":1,
"military_might":1035,
"public":false,
"tag":"QUE",
"slogan":"",
"id":746034084459209223
},
"750446471312466445":{
"emblem":0,
"name":"Phoenix Inc",
"member_count":35,
"level":6,
"military_might":453369,
"public":true,
"tag":"PHOI",
"slogan":"",
"id":750446471312466445
},
"750446518934594062":{
"emblem":11,
"name":"Australia",
"member_count":44,
"level":8,
"military_might":957211,
"public":true,
"tag":"AUST",
"slogan":"Go Australia",
"id":750446518934594062
}
},
"server_version":"v7.190.4-master.000000006"
}
I tried several jq commands:
.alliances_info | .[] | [{alliance_name: .name, alliance_count: .member_count, alliance_level: .level, alliance_power: .military_might, alliance_tag: .tag, alliance_slogan: .slogan, alliance_id: .id}]
or
.alliances_info | .. | objects | [{alliance_name: .name, alliance_c
ount: .member_count, alliance_level: .level, alliance_power: .military_might, alliance_tag: .tag, alliance_slogan: .slog
an, alliance_id: .id}]
But Always get a jq error: parse error: Invalid numeric literal at line 1, column 3
I renounce on the object Building in the first command (and built only a Array) it works. But i need that objects. Any tips?
BR
Timo
Your first query works perfectly well with the given JSON sample. Perhaps you're invoking jq incorrectly. If you have the jq program in a file, say select.jq, you'd invoke jq like so:
jq -f select.jq sample.json
If that doesn't help, then try:
jq empty sample.json
If that fails, there might be something wrong with the encoding of the JSON.
I'm not sure I understand what you want.
Your first attempt works for me, but generates one output for JSON value in the input. That is, I created a file named so.json and put in it your JSON from above:
{
"alliances_info": {
"744085325458334213": {
"emblem": 3,
⋮
}
When I run your program , I get:
$ jq '.alliances_info | .[] | [{alliance_name: .name, alliance_count: .member_count, alliance_level: .level, alliance_power: .military_might, alliance_tag: .tag, alliance_slogan: .slogan, alliance_id: .id}]' so.json
[
{
"alliance_name": "wellwell",
"alliance_count": 1,
"alliance_level": 1,
"alliance_power": 1035,
"alliance_tag": "MELL",
"alliance_slogan": "",
"alliance_id": 744085325458334200
}
]
[
{
"alliance_name": "Brave",
⋮
]
If you want an array at all, you probably want one array containing all the alliances like this:
$ jq '.alliances_info | [ .[] | { alliance_name: .name, alliance_id: .id } ]' so.json
[
{
"alliance_name": "wellwell",
"alliance_id": 744085325458334200
},
{
"alliance_name": "Brave",
"alliance_id": 744128593839678000
},
{
"alliance_name": "Queen",
"alliance_id": 746034084459209200
},
{
"alliance_name": "Phoenix Inc",
"alliance_id": 750446471312466400
},
{
"alliance_name": "Australia",
"alliance_id": 750446518934594000
}
]
Starting from the left,
- .alliances_info looks in its input object for the field named "alliances_info" and outputs its value
- the | next says take the output from the left-hand side and pass those as inputs to the right-hand side.
- right after that first |, I have a [ «jq expressions» ] which tells jq to create one JSON array output for each input; the elements of that array are the outputs of that inner «jq expressions»
- that inner expression starts with .[] which means to produce one output for each JSON value (ignoring the keys) in the input object. For us, that will be the objects named "744085325458334213", "744128593839677958", …
- The next | uses those objects as input and for each, generates a JSON object { alliance_name: .name, alliance_id: .id }
That's why I end up with one JSON array containing 5 JSON objects.
As far as I can tell, you are mostly just renaming a bunch of the fields. For that, you could just do something like this:
$ jq --argjson renameMap '{ "name": "alliance_name", "member_count": "alliance_count", "level": "alliance_level", "military_might": "alliance_power", "tag": "alliance_tag", "slog": "alliance_slogan"}' '.alliances_info |= ( . | [ to_entries[] | ( .value |= ( . | [ to_entries[] | ( .key |= ( if $renameMap[.] then $renameMap[.] else . end ) ) ] | from_entries ) ) ] | from_entries )' so.json
{
"alliances_info": {
"744085325458334213": {
"emblem": 3,
"alliance_name": "wellwell",
"alliance_count": 1,
"alliance_level": 1,
"alliance_power": 1035,
"public": false,
"alliance_tag": "MELL",
"slogan": "",
"id": 744085325458334200
},
"744128593839677958": {
"emblem": 0,
"alliance_name": "Brave",
"alliance_count": 1,
"alliance_level": 1,
"alliance_power": 1035,
"public": false,
"alliance_tag": "GABA",
"slogan": "",
"id": 744128593839678000
},
⋮
},
"server_version": "v7.190.4-master.000000006"
}
well i am a idiot (to be here totally clear). I found the reason (and this is normally a nobrainer...). I read the input from a file and the funny thing is that the file is Unicode but no UTF8. after recoding the command is working fine. Thanks for the help.
BR
Timo
Input:
{"success": true, "results": {"a": …, "b": …, "c": …}}
Desired output, given I want to keep b:
{"success": true, "results": {"b": …}}
Things I tried:
$ jq 'del(select(.results.b | not))'
{"success": true, "results": {"a": …, "b": …, "c": …}}
# removes nothing from "results"
$ jq 'with_entries(select(.key == "success" or .key == "results.b"))'
{"success": true}
# nested comparison not understood; returns only "success"
Thanks!
Here is one solution:
.results |= {b}
Sample Run
$ jq -M '.results |= {b}' <<< '{"success":true, "results":{"a": "…", "b": "…", "c": "…"}}'
{
"success": true,
"results": {
"b": "…"
}
}
Try it online at jqplay.org
Another way using nodejs and shell :
Code :
$ node<<EOF
var obj = $(</tmp/file.json);
delete obj.results.a;
delete obj.results.c;
console.log(JSON.stringify(obj));
EOF
OUTPUT :
{"success":true,"results":{"b":"bbb"}}
I have a JSON file:
$ cat ~/tmp/example1.json
[
{
"keyProp": 11111111111111,
"values": [
"VALUE1"
]
},
{
"keyProp": 2222,
"values": [
"VALUE2"
]
}
]
I want to use jq to select values where keyProp==11111111111111. Expected output is 'VALUE2'
I have tried but without result:
cat ~/tmp/example1.json | jq 'select(.keyProp==11111111111111)'
jq: error (at <stdin>:14): Cannot index array with string "keyProp"
To select a block you need to use the expression described in the docs:
select(boolean_expression)
The function select(foo) produces its input unchanged if foo returns
true for that input, and produces no output otherwise.
It’s useful for filtering lists: [1,2,3] | map(select(. >= 2)) will
give you [2,3].
jq '.[] | select(.id == "second")'
Input [{"id": "first", "val": 1}, {"id": "second", "val": 2}]
Output {"id": "second", "val": 2}
So in this case you need to say:
$ jq '.[] | select(.keyProp==11111111111111)' file
{
"values": [
"VALUE1"
],
"keyProp": 11111111111111
}
To extract the list in value, just say so:
$ jq '.[] | select(.keyProp==11111111111111).values' file
[
"VALUE1"
]
You can even extract the first value by using indexes:
$ jq '.[] | select(.keyProp==11111111111111).values[0]' file
"VALUE1"