How to parse JSON string in Perl

Last updated on October 16, 2020 by Dan Nanni

If you need to parse a JSON-formatted string in Perl, you can use a Perl module called JSON. The JSON module contains JSON-specific decode/encode functions that convert a JSON string into a Perl data structure, and vice versa. Here is how to parse JSON string in Perl.

First, install JSON Perl module from CPAN:

$ sudo perl -MCPAN -e 'install JSON' 

Alternatively, if you are using Ubuntu or Debian, you can install JSON module as follows.

$ sudo apt-get install libjson-pp-perl

You can then use a function called decode_json() which decodes a JSON string, and returns the reference to a corresponding Perl data structure.

The following Perl example shows how to parse JSON string, including JSON object and JSON array.

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

my $json = '{
        "name": "Bob",
        "sex": "Male",
        "address": {
                "city": "San Jose",
                "state": "California"
        },
        "friends":
                [
                        {
                                "name": "Alice",
                                "age": "20"
                        },
                        {
                                "name": "Laura",
                                "age": "23"
                        },
                        {
                                "name": "Daniel",
                                "age": "30"
                        }
                ]
}';

my $decoded = decode_json($json);

# This is a Perl example of parsing a JSON object.

print "City = " . $decoded->{'address'}{'city'} . "n";

# This is a Perl example of parsing a JSON array.

my @friends = @{ $decoded->{'friends'} };
foreach my $f ( @friends ) {
  print $f->{"name"} . "n";
}

The above Perl code snippet will print out the following.

City = San Jose
Alice
Laura
Daniel

If interested, you can check out other tutorials on parsing JSON string, such as using Python language or a Linux command line.

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