How can I convert my JSON to CSV using jq?

Question

I have the following JSON data:

{\"id\":\"111\",\"case\":\"Y\",\"custom\":{\"speech invoked\":\"no\",\"input method\":\"hard\",\"session ID\":\"420\"}}


        

Answer 1

Using Perl and its JSON module:

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use JSON;

my $input = << '__JSON__';
{"id":"111","case":"Y","custom":{"speech invoked":"no","input method":"hard","session ID":"420"}}
__JSON__

my $struct = decode_json($input);

my @header = grep ! ref $struct->{$_}, keys %$struct;
push @header, map keys %{ $struct->{$_} },
              grep ref $struct->{$_},
              keys %$struct;

my @row = grep ! ref, values %$struct;
push @row, map values %$_, grep ref, values %$struct;

say join ',', @header;
say join ',', @row;

Answer 2

Using perl wasn't a good solution for me but after a bit of trial and error I figured out you can do it with just jq using the join() operator.

First make an array of the output you need, then join the array elements using commas.

jq -r '[.case, .custom."speech invoked", .custom."input method"] | join(", ")'

Enjoy. :)

Answer 3

Building upon Joe Harris' answer, you can use the @csv filter so that strings are properly quoted and escaped when necessary :

jq -r '[.case, .custom."speech invoked", .custom."input method"] | @csv'

Answer 4

Here is another solution. If data.json contains the sample data then

jq -M -s -r 'map(.+.custom|del(.custom)) | (.[0]|keys_unsorted), (.[]|[.[]]) | join(",")' data.json

will produce

id,case,speech invoked,input method,session ID
111,Y,no,hard,420

Answer 5

Using jq, you can use this filter:

with_entries(select(.key != "custom")) + .custom
    | to_entries
    | map(.key), map(.value)
    | @csv

Just note that written this way, the "custom" properties will always be written in the end, no matter what order the properties are in.