Having difficulties converting this JSON. It is multi-line similar to what is below. The example data at the bottom is what is reads as-is once unzipped.
An example of what has been tried:
jq -r '(([["user_id","server_received_time","app","device_carrier","$schema","city","uuid","event_time","platform","os_version","amplitude_id","processed_time","user_creation_time","version_name","ip_address","paying","dma","group_properties","user_properties","client_upload_time","$insert_id","event_type","library","amplitude_attribution_ids","device_type","device_manufacturer","start_version","location_lng","server_upload_time","event_id","location_lat","os_name","amplitude_event_type","device_brand","groups","event_properties","data","device_id","language","device_model","country","region","is_attribution_event","adid","session_id","device_family","sample_rate","idfa","client_event_time"]]) + [(.table.All[] | [.user_id,.server_received_time,.app,.device_carrier,.$schema,.city,.uuid,.event_time,.platform,.os_version,.amplitude_id,.processed_time,.user_creation_time,.version_name,.ip_address,.paying,.dma,.group_properties,.user_properties,.client_upload_time,.$insert_id,.event_type,.library,.amplitude_attribution_ids,.device_type,.device_manufacturer,.start_version,.location_lng,.server_upload_time,.event_id,.location_lat,.os_name,.amplitude_event_type,.device_brand,.groups,.event_properties,.data,.device_id,.language,.device_model,.country,.region,.is_attribution_event,.adid,.session_id,.device_family,.sample_rate,.idfa,.client_event_time])])[]|#csv' test.json > test.csv
As well as some other jq options. I need every column regardless of the value, and the values as-is. Does anyone have thoughts on why we are running into issues? One error we get is:
jq: error: try .["field"] instead of .field for unusually named fields at <top-level>, line 1:
Other jq lines have given the following error:
string (...) cannot be csv-formatted, only array
This is an excerpt from one of the JSON files:
{"groups":{},"country":"United States","device_id":"3d-88c-45-b6-ed81277eR","is_attribution_event":false,"server_received_time":"2019-12-17 17:29:11.113000","language":"English","event_time":"2019-12-17 17:27:49.047000","user_creation_time":"2019-11-08 13:15:32.919000","city":"Sure","uuid":"someID","device_model":"Windows","amplitude_event_type":null,"client_upload_time":"2019-12-17 17:29:21.958000","data":{},"library":"amplitude-js\/5.2.2","device_manufacturer":null,"dma":"Washington, DC (Townville, USA)","version_name":null,"region":"Virginia","group_properties":{},"location_lng":null,"device_family":"Windows","paying":null,"client_event_time":"2019-12-17 17:27:59.892000","$schema":12,"device_brand":null,"user_id":"email#gmail.com","event_properties":{"title":"Name","id":"1-253251","applicationName":"SomeName"},"os_version":"18","device_carrier":null,"server_upload_time":"2019-12-17 17:29:11.135000","session_id":1576603675620,"app":231165,"amplitude_attribution_ids":null,"event_type":"CHANGE_PERSPECTIVE","user_properties":{},"adid":null,"device_type":"Windows","$insert_id":"e308c923-d8eb-48c6-8ea5-600","event_id":24,"amplitude_id":515,"processed_time":"2019-12-17 17:29:12.760372","platform":"Web","idfa":null,"os_name":"Edge","location_lat":null,"ip_address":"123.456.78.90","sample_rate":null,"start_version":null}
Thank you!
There are several problems with your attempt.
First, the keys with "$" in their names cannot be specified using the abbreviated .foo syntax; you could use .["$foo"] instead.
Second, #csv expects an array of atomic values. Thus the keys with JSON objects as values must be handled specially.
Third, the "+" is incorrect. The relevant connector here is ",".
With your sample JSON, the following will work:
(["user_id","server_received_time","app","device_carrier","$schema","city","uuid","event_time","platform","os_version","amplitude_id","processed_time","user_creation_time","version_name","ip_address","paying","dma","group_properties","user_properties","client_upload_time","$insert_id","event_type","library","amplitude_attribution_ids","device_type","device_manufacturer","start_version","location_lng","server_upload_time","event_id","location_lat","os_name","amplitude_event_type","device_brand","groups","event_properties","data","device_id","language","device_model","country","region","is_attribution_event","adid","session_id","device_family","sample_rate","idfa","client_event_time"]),
([.user_id,.server_received_time,.app,.device_carrier,.["$schema"],.city,.uuid,.event_time,.platform,.os_version,.amplitude_id,.processed_time,.user_creation_time,.version_name,.ip_address,.paying,.dma,.group_properties,.user_properties,.client_upload_time,.["$insert_id"],.event_type,.library,.amplitude_attribution_ids,.device_type,.device_manufacturer,.start_version,.location_lng,.server_upload_time,.event_id,.location_lat,.os_name,.amplitude_event_type,.device_brand,.groups,.event_properties,.data,.device_id,.language,.device_model,.country,.region,.is_attribution_event,.adid,.session_id,.device_family,.sample_rate,.idfa,.client_event_time]
| map(if type=="object"
then to_entries
| map( "\(.key):\(.value)" )
| join(";")
else . end))
| #csv
A less error-prone solution
Specifying the long list of keys twice makes the above solution error-prone. It would be better to specify the keys just once, and then programatically generate the rows.
Here's a utility function that can be used to this end:
def toa($headers):
. as $in | $headers | map($in[.]);
Or you could handle the object-valued keys inside toa:
def toa($headers):
def flat:
if type == "object" or type == "array"
then to_entries | map( "\(.key):\(.value)" ) | join(";")
else .
end;
. as $in | $headers | map($in[.] | flat);
JSONL
If the input is a stream of JSON objects of the type illustrated in the question, an efficient solution would use inputs with the -n command line option. This could be along the lines of:
print_header,
(inputs | print_row)
Related
I'm writing a bash script to read a JSON file and export the key-value pairs as environment variables. Though I could extract the key-value pairs, I'm struggling to skip those entries that failed to parse by jq.
JSON (key3 should fail to parse)
{
"KEY1":"ABC",
"KEY2":"XYZ",
"KEY3":"---ABC---\n
dskfjlksfj"
}
Here is what I tried
for pair in $(cat test.json | jq -r -R '. as $line | try fromjson catch $line | to_entries | map("\(.key)=\(.value)") | .[]' ); do
echo $pair
export $pair
done
And this is the error
jq: error (at <stdin>:1): string ("{") has no keys
jq: error (at <stdin>:2): string (" \"key1...) has no keys
My code is based on these posts:
How to convert a JSON object to key=value format in jq?
How to ignore broken JSON line in jq?
Ignore Unparseable JSON with jq
Here's a response to the revised question. Unfortunately, it will only be useful in certain limited cases, not including the example you give. (Basically, it depends on jq's parser being able to recover before the end of file.)
while read -r line ; do
echo export "$line"
done < <(< test.json jq -rn '
def do:
try inputs catch null
| objects
| to_entries[]
| "\(.key)=\"\(.value|#sh)\"" ;
recurse(do) | select(.)
')
Note that further refinements may be warranted, especially if there is potentially something fishy about the key names being used as shell variable names.
[Note: this response was made to the original question, which has since been changed. The response essentially assumes the input consists of JSONLines interspersed with other lines.)
Since the goal seems to be to ignore lines that don't have valid key-value pairs, you can simply use catch empty:
while read -r line ; do
echo export "$line"
done < <(test.json jq -r -R '
try fromjson catch empty
| objects
| to_entries[]
| "\(.key)=\"\(.value|#sh)\""
')
Note also the use of #sh and of the shell's read, and the fact that .value (in jq) and $line (in the shell) are both quoted. These are all important for robustness, though further refinements might still be necessary for additional robustness.
Perhaps there is an algorithm that will repair the broken JSON produced by the upstream system. If not, the following is a horrible but possibly useful "hack" that will at least capture KEY1 and KEY2 in the example in the Q:
jq -Rr '
capture("\"(?<key>[^\"]*)\"[ \t]*:[ \t]*(?<value>[^}]+)")
| (.value |= sub("[ \t]+$"; "") ) # trailing whitespace
| if .value|test("^\".*\"") then .value |= sub("\"[ \t]*[,}[ \t]*$"; "\"") else . end
| select(.value | test("^\".*\"$") or (contains("\"")|not) ) # a string or not a string
| "\(.key)=\(.value|#sh)"
'
The broken JSON in the example could be repaired in a number of ways, e.g.:
sed '/\\n$/{N; s/\\n\n/\\n/;}'
produces:
{
"KEY1":"ABC",
"KEY2":"XYZ",
"KEY3":"---ABC---\ndskfjlksfj"
}
At least that's JSON :-)
How do I use jq to convert an arbitrary JSON array of objects to CSV, while objects in this array are nested?
StackOverflow has a sea of questions/answers where specific input or output fields are referenced, but I'd like to have a generic solution that
includes a header row,
works for any JSON input including nested arrays + objects,
allows records that have missing values for keys that are present in other records
does not hard-code any field names,
allows converting the CSV back into the nested JSON structure if needed, and
uses key paths as header names (see the following description).
Dot notation
Many JSON-using products (like CouchDB, MongoDB, …) and libraries (like Lodash, …) use variations of syntax that allows access to nested property values / subfields by joining key fragments with a character, often a dot (‘dot notation’).
An example of a key path like this would be "a.b.0.c" to refer to the deeply nested property in this JSON snippet:
{
"a": {
"b": [
{
"c": 123,
}
]
}
}
Caveat: Using this method is a pragmatic solution for most cases, but means that either dot characters have to be banned in property names, or a more complex (and definitely never used property name) has to be invented for escaping dots in property names / accessing nested fields. MongoDB simply banned usage of "." in documents until v5.0, some libraries have workarounds for field access (Lodash example).
Despite this, for simplicity, a solution should use the described dot syntax in the CSV output’s header for nested properties. Bonus if there is a solution variant that solves this problem, e.g. with JSONPath.
Example JSON array as input
[
{
"a": {
"b": [
{
"c": 123
}
]
}
},
{
"a": {
"b": [
{
"c": "foo \" bar",
"d": "qux"
}
]
}
},
{
"a": {
"b": [
{
"d": 456
}
]
}
}
]
Example CSV output
The output should have a header that includes all fields (even if the object at the first array does not have defined values for all existing key paths).
To make the output intuitively editable by humans, each row should represent one object in the input array.
The expected output should look like this:
"a.b.0.c","a.b.0.d"
123,
"foo "" bar","qux"
,456
Command line
This is what I need:
cat example.json | jq <MISSING CODE HERE>
Solution 1, using dot notation
Here is the jq call to convert your array of nested JSON objects to CSV:
jq -r '(. | map(leaf_paths) | unique) as $cols | map (. as $row | ($cols | map(. as $col | $row | getpath($col)))) as $rows | ([($cols | map(. | map(tostring) | join(".")))] + $rows) | map(#csv) | .[]
The fastest way to try this solution out is to use JQPlay.
The CSV output will have a header row. It will contain all properties that exist anywhere in the input objects, including nested ones, in dot notation. Each input array element will be represented as a single row, properties that are missing will be represented as empty CSV fields.
Using solution 1 in bash or a similar shell
Create the JSON input file…
echo '[{"a": {"b": [{"c": 123}]}},{"a": {"b": [{"c": "foo \" bar","d": "qux"}]}},{"a": {"b": [{"d": 456}]}}]' > example.json
Then use this jq command to output the CSV on the standard output:
cat example.json | jq -r '(. | map(leaf_paths) | unique) as $cols | map (. as $row | ($cols | map(. as $col | $row | getpath($col)))) as $rows | ([($cols | map(. | map(tostring) | join(".")))] + $rows) | map(#csv) | .[]'
…or write the output to example.csv:
cat example.json | jq -r '(. | map(leaf_paths) | unique) as $cols | map (. as $row | ($cols | map(. as $col | $row | getpath($col)))) as $rows | ([($cols | map(. | map(tostring) | join(".")))] + $rows) | map(#csv) | .[]' > example.csv
Converting the data from solution 1 back to JSON
Here is a Node.js example that you can try on RunKit. It converts a CSV generated with the method in solution 1 back to an array of nested JSON objects.
Explanation for solution 1
Here is a longer, commented version of the jq filter.
# 1) Find all unique leaf property names of all objects in the input array. Each nested property name is an array with the components of its key path, for example ["a", 0, "b"].
(. | map(leaf_paths) | unique) as $cols |
# 2) Use the found key paths to determine all (nested) property values in the given input records.
map (. as $row | ($cols | map(. as $col | $row | getpath($col)))) as $rows |
# 3) Create the raw output array of rows. Each row is represented as an array of values, one element per existing column.
(
# 3.1) This represents the header row. Key paths are generated here.
[($cols | map(. | map(tostring) | join(".")))]
+ # 3.2) concatenate the header row with all other rows
$rows
)
# 4) Convert each row to a escaped CSV string.
| map(#csv)
# 5) output each array element directly. Without this, the result would be a JSON array of CSV strings.
| .[]
Solution 2: for input that does have dots in property names
If you do need to support dot characters in property names, you can either use a different separator string for the key path syntax (replace the dot in "." with something else), or replace the map(tostring) | join(".") part with tostring - this yields a JSON array of strings that you can use as key paths - no dot notation needed. Here is a JQPlay with this solution variant.
Full jq command:
jq -r (. | map(leaf_paths) | unique) as $cols | map (. as $row | ($cols | map(. as $col | $row | getpath($col)))) as $rows | ([($cols | map(. | tostring))] + $rows) | map(#csv) | .[]
The output CSV for the variant would look like this then – it’s less readable and not useful for cases where you want humans to intuitively understand the CSV’s header:
"[""a"",""b"",0,""c""]","[""a"",""b"",0,""d""]"
123,
"foo "" bar","qux"
,456
See below for an idea how to convert this format back to a representation in your programming language.
Bonus: Converting the generated CSV back to JSON
If the input's nested properties contain no ".", it’s simple to convert the CSV back to JSON, for example with a library that supports dot notation, or with JSONPath.
JavaScript: Use Lodash's _.set()
Other languages: Find a package/library that implements JSONPath and use selectors like $.a.b.0.c or $['a']['b'][0]['c'] to set each nested property of each record.
Solution 2 (with JSON arrays as headers) allows you to interpret the headers as JSON array strings. Then you can generate a JSON Path from each header, and re-create all records/objects:
"[""a"",""b"",0,""c""]" (CSV)
→ ["a","b",0,"c"] (array of key-path components after unescaping and parsing as JSON)
→ $.["a"]["b"][0]["c"] (JSONPath)
→ { a: { b: [{c: … }] } } (Nested regenerated object)
I've written an example Node.js script to convert a CSV like this back to JSON. You can try solution 2 in RunKit.
The following tocsv and fromcsv functions provide a solution to the stated problem except for one complication regarding requirement (6) concerning the headers. Essentially, this requirement can be met using the functions given here by adding a matrix transposition step.
Whether or not a transposition step is added, the advantage of the approach taken here is that there are no restrictions on the JSON keys or values. In particular, they may
contain periods (dots), newlines and/or NUL characters.
In the example, an array of objects is given, but in fact any stream of valid JSON documents could be used as input to tocsv; thanks to the magic of jq, the original stream will be recreated by fromcsv (in the sense of entity-by-entity equality).
Of course, since there is no CSV standard, the CSV produced by the
tocsv function might not be understood by all CSV processors. In
particular, please note that the tocsv function defined here maps
embedded newlines in JSON strings or key names to the two-character
string "\n" (i.e., a literal backslash followed by the letter "n");
the inverse operation performs the inverse translation to meet the
"round-trip" requirement.
(The use of tail is just to simplify the presentation; it would be
trivial to modify the solution to make it an only-jq one.)
The CSV is generated on the assumption that any value can be
included in a field so long as (a) the field is quoted, and (b)
double-quotes within the field are doubled.
Any generic solution that supports "round-trips" is bound to be
somewhat complicated. The main reason why the solution presented here is
more complex than one might expect is because a third column is
added, partly to make it easy to distinguish between integers and
integer-valued strings, but mainly because it makes it easy to
distinguish between the size-1 and size-2 arrays produced by jq's
--stream option. Needless to say, there are other ways
these issues could be addressed; the number of calls to jq could
also be reduced.
The solution is presented as a test script that checks the round-trip requirement on a telling test case:
#!/bin/bash
function json {
cat<<EOF
[
{
"a": 1,
"b": [
1,
2,
"1"
],
"c": "d\",ef",
"embed\"ed": "quote",
"null": null,
"string": "null",
"control characters": "a\u0000c",
"newline": "a\nb"
},
{
"x": 1
}
]
EOF
}
function tocsv {
jq -ncr --stream '
(["path", "value", "stringp"],
(inputs | . + [.[1]|type=="string"]))
| map( tostring|gsub("\"";"\"\"") | gsub("\n"; "\\n"))
| "\"\(.[0])\",\"\(.[1])\",\(.[2])"
'
}
function fromcsv {
tail -n +2 | # first duplicate backslashes and deduplicate double-quotes
jq -rR '"[\(gsub("\\\\";"\\\\") | gsub("\"\"";"\\\"") ) ]"' |
jq -c '.[2] as $s
| .[0] |= fromjson
| .[1] |= if $s then . else fromjson end
| if $s == null then [.[0]] else .[:-1] end
# handle newlines
| map(if type == "string" then gsub("\\\\n";"\n") else . end)' |
jq -n 'fromstream(inputs)'
}
# Check the roundtrip:
json | tocsv | fromcsv | jq -s '.[0] == .[1]' - <(json)
Here is the CSV that would be produced by json | tocsv, except that SO seems to disallow literal NULs, so I have replaced that by \0:
"path","value",stringp
"[0,""a""]","1",false
"[0,""b"",0]","1",false
"[0,""b"",1]","2",false
"[0,""b"",2]","1",true
"[0,""b"",2]","false",null
"[0,""c""]","d"",ef",true
"[0,""embed\""ed""]","quote",true
"[0,""null""]","null",false
"[0,""string""]","null",true
"[0,""control characters""]","a\0c",true
"[0,""newline""]","a\nb",true
"[0,""newline""]","false",null
"[1,""x""]","1",false
"[1,""x""]","false",null
"[1]","false",null
Let's say I have some JSON in a file, it's a subset of JSON data extracted from a larger JSON file - that's why I'll use stream later in my attempted solution - and it looks like this:
[
{"_id":"1","#":{},"article":false,"body":"Hello world","comments":"3","createdAt":"20201007200628","creator":{"id":"4a7ba8fd719d43598b977dd548eed6aa","bio":"","blocked":false,"followed":false,"human":false,"integration":false,"joined":"20201007200628","muted":false,"name":"mkscott","rss":false,"private":false,"username":"mkscott","verified":false,"verifiedComments":false,"badges":[],"score":"0","interactions":258,"state":1},"depth":"0","depthRaw":0,"hashtags":[],"id":"2d4126e342ed46509b55facb49b992a5","impressions":"3","links":[],"sensitive":false,"state":4,"upvotes":"0"},
{"_id":"2","#":{},"article":false,"body":"Goodbye world","comments":"3","createdAt":"20201007200628","creator":{"id":"4a7ba8fd719d43598b977dd548eed6aa","bio":"","blocked":false,"followed":false,"human":false,"integration":false,"joined":"20201007200628","muted":false,"name":"mkscott","rss":false,"private":false,"username":"mkscott","verified":false,"verifiedComments":false,"badges":[],"score":"0","interactions":258,"state":1},"depth":"0","depthRaw":0,"hashtags":[],"id":"2d4126e342ed46509b55facb49b992a5","impressions":"3","links":[],"sensitive":false,"state":4,"upvotes":"0"}
],
[
{"_id":"55","#":{},"article":false,"body":"Hello world","comments":"3","createdAt":"20201007200628","creator":{"id":"3a7ba8fd719d43598b977dd548eed6aa","bio":"","blocked":false,"followed":false,"human":false,"integration":false,"joined":"20201007200628","muted":false,"name":"mkscott","rss":false,"private":false,"username":"jkscott","verified":false,"verifiedComments":false,"badges":[],"score":"0","interactions":258,"state":1},"depth":"0","depthRaw":0,"hashtags":[],"id":"2d4126e342ed46509b55facb49b992a5","impressions":"3","links":[],"sensitive":false,"state":4,"upvotes":"0"},
{"_id":"56","#":{},"article":false,"body":"Goodbye world","comments":"3","createdAt":"20201007200628","creator":{"id":"3a7ba8fd719d43598b977dd548eed6aa","bio":"","blocked":false,"followed":false,"human":false,"integration":false,"joined":"20201007200628","muted":false,"name":"mkscott","rss":false,"private":false,"username":"jkscott","verified":false,"verifiedComments":false,"badges":[],"score":"0","interactions":258,"state":1},"depth":"0","depthRaw":0,"hashtags":[],"id":"2d4126e342ed46509b55facb49b992a5","impressions":"3","links":[],"sensitive":false,"state":4,"upvotes":"0"}
]
It describes 4 posts written by 2 different authors, with unique _id fields for each post. Both authors wrote 2 posts, where 1 says "Hello World" and the other says "Goodbye World".
I want to match on the word "Hello" and return the _id only for fields containing "Hello". The expected result is:
1
55
The closest I could come in my attempt was:
jq -nr --stream '
fromstream(1|truncate_stream(inputs))
| select(.body %like% "Hello")
| ._id
' <input_file
Assuming the input is modified slightly to make it a stream of the arrays as shown in the Q:
jq -nr --stream '
fromstream(1|truncate_stream(inputs))
| select(.body | test("Hello"))
| ._id
'
produces the desired output.
test uses regex matching. In your case, it seems you could use simple substring matching instead.
Handling extraneous commas
Assuming the input has commas between a stream of valid JSON exactly as shown, you could presumably use sed to remove them first.
Or, if you want an only-jq solution, use the following in conjunction with the -n, -r and --stream command-line options:
def iterate:
fromstream(1|truncate_stream(inputs?))
| select(.body | test("Hello"))
| ._id,
iterate;
iterate
(Notice the "?".)
The streaming parser (invoked with --stream) is usually not needed for the kind of task you describe, so in this response, I'm going to assume that the following (or a variant thereof) will suffice:
.[]
| select( .body | test("Hello") )._id
This of course assumes that the input is valid JSON.
Handling comma-delimited JSON
If your input is a comma-delimited stream of JSON as shown in the Q, you could use the following in conjunction with the -n command-line option:
# This is a variant of the built-in `recurse/1`:
def iterate(f): def r: f | (., r); r;
iterate( inputs? | .[] | select( .body | test("Hello") )._id )
Please note that this assumes that whatever occurs on a line after a delimiting comma can be ignored.
I have the following JSON content in a file.json.
I need only a particular key field from all this overwhelming information.
Let us assume that I need web_url,
The problem here is there are multiple key field with "web_url".
How do only get the web_url field I am after?
[{"id":196,"iid":1,"project_id":233,"title":"DEV to Master","description":"","state":"merged","created_at":"2019-12-04T14:14:35.424-06:00","updated_at":"2019-12-04T14:14:47.310-06:00","merged_by":{"id":122,"name":"Sengoku","username":"sengk","state":"active","avatar_url":"https://secure.gravatar.com/avatar/7cvffgfgfgfgf9eb1348d0ba7795a076?s=80\u0026d=identicon","web_url":"https://gitlaboo.tests.com/sengk"},"merged_at":"2019-12-04T14:14:47.468-06:00","closed_by":null,"closed_at":null,"target_branch":"master","source_branch":"DEV","upvotes":0,"downvotes":0,"author":{"id":122,"name":"Sengoku","username":"sengk","state":"active","avatar_url":"https://secure.gravatar.com/avatar/7fgdfdgdfgdvfg9eb1348d0ba7795a076?s=80\u0026d=identicon","web_url":"https://gitlaboo.tests.com/sengk"},"assignee":{"id":122,"name":"Sengoku","username":"sengk","state":"active","avatar_url":"https://secure.gravatar.com/avatar/7afsdfdvdfvfde24f89eb1348d0ba7795a076?s=80\u0026d=identicon","web_url":"https://gitlaboo.tests.com/sengk"},"source_project_id":233,"target_project_id":233,"labels":[],"work_in_progress":false,"milestone":null,"merge_when_pipeline_succeeds":false,"merge_status":"can_be_merged","sha":"6318e51ea8czfdfsdvdfvdfbc02988ba62c71e5774107e","merge_commit_sha":"6dc5vdfvdfgdfg5bf14e97dea949b8584c0c68d6","user_notes_count":0,"discussion_locked":null,"should_remove_source_branch":null,"force_remove_source_branch":false,"web_url":"https://gitlaboo.tests.com/demo/frog/merge_requests/1","time_stats":{"time_estimate":0,"total_time_spent":0,"human_time_estimate":null,"human_total_time_spent":null},"squash":false}]
You have 4 web_url in your JSON.
Can check the below results,
.[] | .web_url
.[] | .merged_by.web_url
.[] | .author.web_url
.[] | .assignee.web_url
If the question is essentially how to find the needle in the haystack, the answer is: use paths; more specifically, in your case:
jq -c 'paths(. == "https://gitlaboo.tests.com/demo/frog/merge_requests/1")
| select(.[-1] == "web_url")
' file.json
The output gives the path as a JSON array:
[0,"web_url"]
This can be used directly in jq (using getpath/1), or as the basis for a direct query:
.[0].web_url
I'm working on storing around 200 000 Json objects into a CSV file. But the problem is that any 2 JSON Objects might be different (having different key names).
I thought about creating a HashSet and traverse through all objects once so as to get column names for my CSV file. But this process is apparently taking too much time.
Is there another way to add columns to a CSV file dynamically?
One approach would be to use jq ("Json Query"):
def tocsv:
if length == 0 then empty
else
(.[0] | keys_unsorted) as $keys
| (map(keys) | add | unique) as $allkeys
| ($keys + ($allkeys - $keys)) as $cols
| ($cols, (.[] as $row | $cols | map($row[.])))
| #csv
end ;
tocsv
For example, assuming the above is in a file named json2csv.jq and that the input is in in.json:
jq -r -f json2csv.jq in.json
The above program constructs the header line by starting with the key names of the first object (in the order in which they appear there), and then extends the header line as required.
For more about jq, see https://stedolan.github.io/jq
Another approach would be to use in2csv, part of the csvkit tookit -- see https://csvkit.readthedocs.org