Is it possible to use a variable to hold a dot notation path? (I'm probably not using the correct term.)
For example, given the following json:
{
"people": [
{
"names": {
"given": "Alice",
"family": "Smith"
},
"id": 47
},
{
"id": 42
}
]
}
Is it possible to construct something like:
.names.given as $ng | .people[] | select(.id==47) | ($ng)
and output "Alice"?
The idea is to allow easier modification of a complex expression. I've tried various parens and quotes with increasing literal results ('.names.given' and '$ng')
The answer is no and yes: as you've seen, once you write an expression such as .names.given as $ng, $ng holds the JSON values, not the path.
But jq does support path expressions in the form of arrays of strings and/or non-negative integers. These can be used to access values in conjunction with the built-in getpath/1.
So you could, for example, write something along the lines of:
["names", "given"] as $ng
| .people[]
| select(.id==47)
| getpath($ng)
Converting jq paths to JSON arrays
It's possible to convert a "dot notation" path into an "array path" using path/1; e.g. the assignment to $ng above could be written as:
(null | path(.names.given)) as $ng
Your question and the example you provided seems very confusing to me. The jist that I got is that you want to assign a name to a value obtained from dot notation and then use it at a later point in time.
See if this is of any help -
.people | map(select(.id = 47))[0].names.given as $ng | $ng
Related
I have a json file input.json thus:
{
"foo":{
"prefix":"abc",
"body":[1,2,3]
},
"bar":{
"prefix":"def",
"body":[4,5,6]
}
}
I would like to sort it by the outer object names, with "bar" coming before "foo" in alphabetical order like so:
{
"bar":{
"prefix":"def",
"body":[4,5,6]
},
"foo":{
"prefix":"abc",
"body":[1,2,3]
}
}
to produce file output.json.
Versions of this question have been asked of Java/Javascript (here and here)
Is there a way to accomplish this using a command line tool like sed/awk or boost.json?
Using jq, you could use the keys built-in to get the key names in sorted order and form the corresponding value object
jq 'keys[] as $k | { ($k) : .[$k] }' json
Note that jq does have a field --sort-keys option, which cannot be used here, as it internally sorts the inner level objects as well.
Here's a variable-free jq solution:
to_entries | sort_by(.key) | from_entries
It is also worth noting that gojq, the Go implementation of jq, currently always sorts the keys within all JSON objects.
Select objects based on value of variable in object using jq
That shows how to return values directly above the selection criteria but how would I get another object that was adjacent to a value above my selection criteria?
Given the data below, what jq invocation would return the French name of planets whose moon(s) have been spoiled? (this is a structural reproduction of the live data with which I am working -- which actually uses the word "value" in this way, so that's not helping)
{"kind":"solarsystem","name":"Sol",
"Planets": [
{ "kind":"habitable",
"names": { "english":"Earth","french":"Terre"},
"satellites" : [
{"name":"The Moon",
"parameters": [
{"name":"diameter", "intValue":"3476"},
{"name":"diameter_units", "value":"km"},
{"name":"unspoiled","value":"no"}]}]},
{"kind":"uninhabitable",
"names": {"english":"Mars","french":"Mars"},
"satellites" : [
{"name":"Phobos",
"parameters": [
{"name":"diameter", "intValue":"2200"},
{"name":"diameter_units", "value":"m"},
{"name":"unspoiled","value":"yes"}]},
{"name":"Deimos",
"parameters": [
{"name":"diameter", "intValue":"1200"},
{"name":"diameter_units", "value":"m"},
{"name":"unspoiled","value":"yes"}]}]}]}
The program below selects planets whose moons have all been spoiled. As each parameter is a name-value pair, we can use from_entries to transform the array of parameters into an object and retrieve the unspoiled status with just .unspoiled, and thus avoid another select to find the parameter we're interested in.
.Planets[] | select(.satellites | all(.parameters | from_entries .unspoiled == "no")) .names.french
If a single spoiled moon is enough, change all to any.
Online demo
And here, also a solution for the same JSON query using an alternative tool (jtc):
In the simplest form, the following will do:
bash $ <file.json jtc -w'[value]:<no>:[-5][names][french]'
"Terre"
However, that solution will return planet's french name for each of the moon, e.g., for spoiled moons it would give this:
bash $ <file.json jtc -w'[value]:<yes>:[-5][names][french]'
"Mars"
"Mars"
bash $
For the case when there're multiple moons but the name is required only once, strengthen the query like this (showcasing here spoiled moons):
bash $ <file.json jtc -w'<satellites>l:[value]:<yes>[-5][names][french]'
"Mars"
bash $
PS. I'm a deveoper of jtc unix JSON processor
PPS. the above disclaimer is required by SO.
Update:
the answer was updated based on discussion in comments with #oguzismail to enhance structural relationship between value and french labels so that other (irrelevant) possible value matches won't trigger false positives.
If, by a chance, the structural relation [-5][names] is not enough, the query then can be ultimately enhanced by inserting <unspoiled>[-1] before [value]... lexeme
I need to download application JAR for execution, and I managed to figure it out up to this step part in my script:
jq '.files[] | select(.uri | contains("RELEASE") and contains(".jar"))'
This gives me a bunch of results that looks like multiple blocks of this:
{
other versions
}
{
"uri": "/2.0.6-RELEASE/app-name-2.0.6-RELEASE.jar",
"size": 32981192,
"lastModified": "2020-02-05T14:21:06.728-05:00",
"folder": false,
"sha1": "whatever",
"sha2": "whatever2",
"mdTimestamps": {
"properties": "2020-02-05T14:21:13.468-05:00"
}
}
Based on the documentation, I tried to extend this to:
jq '.files[] | select(.uri | contains("RELEASE") and contains(".jar")) | max_by(.lastModified)'
But it returns error
jq: error (at <stdin>:3284): Cannot index string with string "lastModified"
Documentation is vague on combining all the different search filters together.. I am not sure what is the correct syntax, please.
My goal: Retrieve only one element, ideally just the URI string so that I can use that to fetch the JAR directly on my next command without further processing.
I also tried the documented syntax for max_by with suffix: | {uri} - same error.
max_by requires an array as input, so in the spirit of your attempt, you might wish to consider:
.files
| map( select(.uri | contains("RELEASE")
and contains(".jar")))
| max_by(.lastModified)
p.s.
In future, please follow the guidelines at
http://stackoverflow.com/help/mcve
On the jq manual page there are a few examples of output formatting, particularly some shortcuts for when you want to just echo exactly what was in the input JSON.
What if I want to echo exactly what was in the input, but only for keys that match a certain pattern?
For example, given input like so ...
[
{"Name":"Widgets","Size":10,"SymUS":"Widg","SymCN":"Zyin","SymJP":"Kono"},
{"Name":"Blodgets","Size":400,"SymUS":"Blodg","SymAU":"Blod","SymJP":"Kado"},
{"Name":"Fonzes","Size":11,"SymRU":"Fyet","SymBR":"Foao"}
]
Say I want to select all objects where the Name ends in "ets" and then display the Name and all attributes of the form Sym*. All I know about those attributes is that there will be one or more per JSON object, and the names have the format Sym followed by a two-letter ISO country code.
I would like to just do this:
jq '.[] | select(.Name | endswith("ets")) | {Name, Sym*}'
but that's not a thing.
Is this just not something jq is designed to handle in a single operation? Should I do a first pass through the file to collect all the possible keys and then list them all explicitly via a slurpfile?
The key to a simple solution to the problem is to_entries, as described in the online manual. With your example data, the following filter produces the output shown below, in accordance with what I understand to be the expectations:
.[]
| select(.Name | test("ets$"))
| {Name} + (to_entries | map(select(.key|test("^Sym"))) | from_entries)
You might want to refine the regex tests, and/or make other minor adjustments.
Output:
{
"Name": "Widgets",
"SymUS": "Widg",
"SymCN": "Zyin",
"SymJP": "Kono"
}
{
"Name": "Blodgets",
"SymUS": "Blodg",
"SymAU": "Blod",
"SymJP": "Kado"
}
Say I have the following JSON, stored in my variable jsonVariable.
{
"id": 1,
"details": {
"username": "jamesbrown",
"name": "James Brown"
}
}
I parse this JSON with jq using the following:
echo $jsonVariable | jq '.details.name | select(.name == "James Brown")'
This would give me the output
James Brown
But what if I want to get the id of this person as well? Now, I'm aware this is a rough and simple example - the program I'm working with at the moment is 5 or 6 levels deep with many different JQ functions other than select. I need a way to select a parent's field when I am already 5 or 6 layers deep after carrying out various methods of filtering.
Can anyone help? Is there any way of 'going in reverse', back up to the parent? (Not sure if I'm making sense!)
For a more generic approach, save the value of the "parent" element at the detail level you want, then pipe it at the end of your filter:
jq '. as $parent | .details.name | select(. == "James Brown") | $parent'
Of course, for the trivial case you expose, you could omit this entirely:
jq 'select(.details.name == "James Brown")'
Also, consider that if your selecting filters return many matches for a single parent object, you will receive a copy of the parent object for each match. You may wish to make sure your select filters only return one element at the parent level by wrapping all matches below parent level into an array, or to deduplicate the final result with unique.
Give this a shot:
echo $jsonVariable | jq '{Name: .details.name, Id: .Id} | select(.name == "James Brown")'
Rather than querying up to the value you're testing for, query up to the root object that contains the value you're querying on and the values you wish to select.
You need the object that contains both the id and the name.
$ jq --arg name 'James Brown' 'select(.details.name == $name).id' input.json