CODEWITHSUNDEEP
jsonperlbashsedawk
DPC
DPC

Reputation: 33

Parsing JSON file using sed or perl

I have a json file that requires parsing. Using scripting like sed/awk or perl, how to extract value30 and substitute that to value6 prefixed by string "XX" (eg. XX + value30). Where:

 [
   {"field6" : "value6", "field30" : "value30" },
   { "field6" : "value6", "field30" : "value30" }
 ]

Upvotes: 1

Views: 717

Answers (1)

Kyle Burton
Kyle Burton

Reputation: 27538

If I understand you correctly, this program should do what you're after:

use JSON qw(decode_json encode_json);
use strict;
use warnings;

# set the input line separator to undefined so the next read (<>) reads the entire file
undef $/; 
# read the entire input (stdin or a file passed on the command line) and parse it as JSON
my $data = decode_json(<>);

my $from_field = "field6";
my $to_field   = "field30";

for (@$data) {
  $_->{$to_field} = $_->{$from_field};
}

print encode_json($data), "\n";

It relies on the JSON module being installed, which you can install via cpanm (which should be available in most modern Perl distributions):

cpanm install JSON

If the program is in the file substitute.pl and your json array is in data.json, then you would run it as:

perl substitute.pl data.json
# or
cat data.json | perl substitute.pl

It should produce:

[{"field30":"value6","field6":"value6"},{"field30":"value6","field6":"value6"}]

Replacing field30's value iwth field6's.

Is this what you were attempting to do?

Upvotes: 3

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