I have this json code:
{
"kind": "something",
"rules": [
{
"rule1": [
"something1",
"something2",
"something3"
],
"rule2": "something"
}
]
}
I want to add something4 to rule1. How can I do this in Ruby?
thanks
Let json_string be your JSON string
require 'json'
h = JSON.parse(json_string)
h["rules"][0]["rule1"] << "something4"
Your Nesting Structure Uses Keys and Indexes
Your problem is that your JSON is really poorly-designed for finding specific keys, because the various rules are actually wrapped inside an array. In your example, you only have one, but if you have more array elements then you've got to find the right array element to modify. It can be done with a lot of work via Enumerable#each_with_index or a related method, but if you are confident of the structure of your JSON you can take a shortcut.
require 'json'
json = <<~'EOF'
{
"kind": "something",
"rules": [
{
"rule1": [
"something1",
"something2",
"something3"
],
"rule2": "something"
}
]
}
EOF
# Get the first array from "rules", and append the string
# to the array inside the hash value referenced by the
# "rule1" key.
hash['rules'].first['rule1'] << 'something4'
puts JSON.pretty_generate(hash)
{
"kind": "something",
"rules": [
{
"rule1": [
"something1",
"something2",
"something3",
"something4"
],
"rule2": "something"
}
]
}
In the real world, you'd likely have to iterate over the rules array to find the index of the array element you want to modify. After that, you can find the rule1 key and append the value you want to the value's hash.
Saying that you assign that code to a variable
settings = {
"kind": "something",
"rules": [
{
"rule1": [
"something1",
"something2",
"something3"
],
"rule2": "something"
}
]
}
you can do this:
settings["rules"][0]["rule1"] << "test"
Related
I have a nested JSON in a field that contains multiple important keys that I would like to retrieve as an array:
{
"tasks": [
{
"id": "task_1",
"name": "task_1_name",
"assignees": [
{
"id": "assignee_1",
"name": "assignee_1_name"
}
]
},
{
"id": "task_2",
"name": "task_2_name",
"assignees": [
{
"id": "assignee_2",
"name": "assignee_2_name"
},
{
"id": "assignee_3",
"name": "assignee_3_name"
}
]}]}
All the queries that I've tried so far fx ( $.tasks.*.assignees..id) and many others have returned
[
"assignee_1",
"assignee_2",
"assignee_3"
]
But what I need is:
[
["assignee_1"],
["assignee_2", "assignee_3"]
]
Is it possible to do with JSONPath or any script inside of it, without involving 3rd party tools?
The problem you're facing is that tasks and assignees are arrays. You need to use [*] instead of .* to get the items in the array. So your path should look like
$.tasks[*].assignees[*].id
You can try it at https://json-everything.net/json-path.
NOTE The output from my site will give you both the value and its location within the original document.
Edit
(I didn't read the whole thing :) )
You're not going to be able to get
[
["assignee_1"],
["assignee_2", "assignee_3"]
]
because, as #Tomalak mentioned, JSON Path is a query language. It's going to remove all structure and return only values.
When I run the jq command to parse a json document from the amazon cli I have the following problem.
I’m parsing through the IP address and a tag called "Enviroment". The enviroment tag in the instance does not exist therefore it does not throw me any result.
Here's an example of the relevant output returned by the AWS CLI
{
"Reservations": [
{
"Instances": [
{
"PrivateIpAddress": "10.0.0.1",
"Tags": [
{
"Key": "Name",
"Value": "Balance-OTA-SS_a"
},
{
"Key": "Environment",
"Value": "alpha"
}
]
}
]
},
{
"Instances": [
{
"PrivateIpAddress": "10.0.0.2",
"Tags": [
{
"Key": "Name",
"Value": "Balance-OTA-SS_a"
}
]
}
]
}
]
}
I’m running the following command
aws ec2 describe-instances --filters "Name=tag:Name,Values=Balance-OTA-SS_a" | jq -c '.Reservations[].Instances[] | ({IP: .PrivateIpAddress, Ambiente: (.Tags[]|select(.Key=="Environment")|.Value)})'
## output
empty
How do I show the IP address in the output of the command even if the enviroment tag does not exist?
Regards,
Let's assume this input:
{
"Reservations": [
{
"Instances": [
{
"PrivateIpAddress": "10.0.0.1",
"Tags": [
{
"Key": "Name",
"Value": "Balance-OTA-SS_a"
},
{
"Key": "Environment",
"Value": "alpha"
}
]
}
]
},
{
"Instances": [
{
"PrivateIpAddress": "10.0.0.2",
"Tags": [
{
"Key": "Name",
"Value": "Balance-OTA-SS_a"
}
]
}
]
}
]
}
This is the format returned by describe-instances, but with all the irrelevant fields removed.
Note that tags is always a list of objects, each of which has a Key and a Value. This format is perfect for from_entries, which can transform this list of tags into a convenient mapping object. Try this:
.Reservations[].Instances[] |
{
IP: .PrivateIpAddress,
Ambiente: (.Tags|from_entries.Environment)
}
{"IP":"10.0.0.1","Ambiente":"alpha"}
{"IP":"10.0.0.2","Ambiente":null}
That answers how to do it. But you probably want to understand why your approach didn't work.
.Reservations[].Instances[] |
{
IP: .PrivateIpAddress,
Ambiente: (.Tags[]|select(.Key=="Environment")|.Value)
}
The .[] filter you're using on the tags can return zero or multiple results. Similarly, the select filter can eliminate some or all items. When you apply this inside an object constructor (the expression from { to }), you're causing that whole object to be created a variable number of times. You need to be very careful where you use these filters, because often that's not what you want at all. Often you instead want to do one of the following:
Wrap the expression that returns multiple results in an array constructor [ ... ]. That way instead of outputting the parent object potentially zero or multiple times, you output it once containing an array that potentially has zero or multiple items. E.g.
[.Tags[]|select(.Key=="Environment")]
Apply map to the array to keep it an array but process its contents, e.g.
.Tags|map(select(.Key=="Environment"))
Apply first(expr) to capture only the first value emitted by the expression. If the expression might emit zero items, you can use the comma operator to provide a default, e.g.
first((.Tags[]|select(.Key=="Environment")),null)
Apply some other array-level function, such as from_entries.
.Tags|from_entries.Environment
You can either use an if ... then ... else ... end construct, or //. For example:
.Reservations[].Instances[]
| {IP: .PrivateIpAddress} +
({Ambiente: (.Tags[]|select(.Key=="Environment")|.Value)}
// null)
I have have a JSON file where I have IDs with tasks. Some tasks can be empty. I want to put the ID into the tasks where tasks are not empty.
[
{
"id": 1961126,
"tasks": [
{
"id": 70340700,
"title": "Test1",
},
{
"id": 69801130,
"title": "Test15A",
}
]
},
{
"id": 1961126,
"tasks": []
}
]
I would like to get the tasks array updated to look like
[
{
"id": 1961126,
"tasks": [
{
**"sId":1961126,**
"id": 70340700,
"title": "Test1",
},
{
**"sId":1961126,**
"id": 69801130,
"title": "Test15A",
}
]
},
{
"id": 1961126,
"tasks": []
}
]
I can't figure out how to get the id from the object into the nested array. Here is what I have come up with
jq 'map(.tasks[0]|select( . != null )|.sId = .id)' file.json
This is only pulling in the same id. I have tired to put in [].id but I get a error Cannot index number with string "id". I am still learning how to deal with nested arrays and objects.
Save the ID in a variable and add it as a new field to each array member.
jq 'map(.id as $sId | .tasks[] += {$sId})' file.json
Demo
Note #1: Get rid of the final , within each object (see the Demo), as it's not proper JSON.
Note #2: Object fields generally have no order, but if you want to have the propagated ID shown first, as seen in your expected output, you could try to replace += {$sId} (which by itself is shorthand for |= . + {$sId}) with |= {$sId} + . to flip the order of generation (Demo). Although there is no guarantee that it stays that way with further processing.
My jq command returns objects in brackets but without comma separators. But I would like to create a new json string from it.
This call finds all elements of arr that have a FooItem in them and then returns texts from the nested array at index 3:
jq '.arr[] | select(index("FooItem")) | .[3].texts'
on this json (The original has more elements ):
{
"arr": [
[
"create",
"w199",
"FooItem",
{
"index": 0,
"texts": [
"aBarfoo",
"avalue"
]
}
],
[
"create",
"w200",
"NoItem",
{
"index": 1,
"val": 5,
"hearts": 5
}
],
[
"create",
"w200",
"FooItem",
{
"index": 1,
"texts": [
"mybarfoo",
"bValue"
]
}
]
]
}
returns this output:
[
"aBarfoo",
"avalue"
]
[
"mybarfoo",
"bValue"
]
But I'd like to create a new json from these objects that looks like this:
{
"arr": [
[
"aBarfoo",
"avalue"
],
[
"mybarfoo",
"bValue"
]
]
}
Can jq do this?
EDIT
One more addition: Considering that texts also has strings of zero length, how would you delete those/not have them in the result?
"texts": ["",
"mybarfoo",
"bValue",
""
]
You can always embed a stream of (zero or more) JSON entities within some other JSON structure by decorating the stream, that is, in the present case, by wrapping the STREAM as follows:
{ arr: [ STREAM ] }
In the present case, however, we can also take the view that we are simply editing the original document, and accordingly use a variation of the map(select(...)) idiom:
.arr |= map( select(index("FooItem")) | .[3].texts)
This latter approach ensures that the context of the "arr" key is preserved.
Addendum
To filter out the empty strings, simply add another map(select(...)):
.arr |= map( select(index("FooItem"))
| .[3].texts | map(select(length>0)))
All the examples I've seen so far "reduce" the output (filter out) some part. I understand how to operate on the part of the input I want to, but I haven't figured out how to output the rest of the content "untouched".
The particular example would be an input file with several high level entries "array1", "field1", "array2", "array3" say. Each array contents is different. The specific processing I want to do is to sort "array1" entries by a "name" field which is doable by:
jq '.array1 | sort_by(.name)' test.json
but I also want this output as "array1" as well as all the other data to be preserved.
Example input:
{
"field1": "value1",
"array1":
[
{ "name": "B", "otherdata": "Bstuff" },
{ "name": "A", "otherdata": "Astuff" }
],
"array2" :
[
array2 stuff
],
"array3" :
[
array3 stuff
]
}
Expected output:
{
"field1": "value1",
"array1":
[
{ "name": "A", "otherdata": "Astuff" },
{ "name": "B", "otherdata": "Bstuff" }
],
"array2" :
[
array2 stuff
],
"array3" :
[
array3 stuff
]
}
I've tried using map but I can't seem to get the syntax correct to be able to handle any type of input other than the array I want to be sorted by name.
Whenever you use the assignment operators (=, |=, +=, etc.), the context of the expression is kept unchanged. So as long as your top-level filter(s) are assignments, in the end, you'll get the rest of the data (with your changes applied).
In this case, you're just sorting the array1 array so you could just update the array.
.array1 |= sort_by(.name)