Unable to iterate over an array in hash in Perl script

Question

Please help me resolve this issue

pre_package_config.pm

use strict;
our %pre_pkg_configs;

$pre_pkg_configs{locDbList}=['default','default_test'];

second.pl

#!/usr/bin/perl
use Expect;
use strict;

our %pre_pkg_configs;

my  $pre_pkg_file = './pre_package_config.pm';

eval {require $pre_pkg_file};

foreach my $db ( $pre_pkg_configs{locDbList} ){
    print $db;
}

Output:

ARRAY (0x10092ae88)

Should have been:

default default_test

When debugging, use the Data::Dumper module to print your debugging information. It will make things much easier for you. — TLP
– TLP, Commented Jan 18, 2013 at 11:54

melpomene · Accepted Answer · 2013-01-18 11:49:10Z

3

$pre_pkg_configs{locDbList} is a single (scalar) value. Iterating over it would simply give you that one value (which happens to be a reference to an array). If you want to iterate over the contents of that array, you need to dereference:

for my $db (@{ $pre_pkg_configs{locDbList} }) {
    print $db;
}

Note that this will output defaultdefault_test, not default default_test. The easiest way to get the latter would be:

print join(" ", @{ $pre_pkg_configs{locDbList} }), "\n";

To learn more about references, see perldoc perlreftut.
(Also, you should use warnings; in every file in addition to use strict;.)

answered Jan 18, 2013 at 11:49

melpomene

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3 Comments

sakhunzai Over a year ago

but I have set the $pre_pkg_configs{locDbList} an array in previous file ? e.g $pre_pkg_configs{locDbList}=['default','default_test'];

sakhunzai Over a year ago

What I should do to make $pre_pkg_configs{locDbList} an array over which I can iterate ?

melpomene Over a year ago

@sakhunzai No, that's a reference to an array, not an array. Hashes can't contain arrays, they can only contain scalars. See perlreftut.

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Unable to iterate over an array in hash in Perl script

pre_package_config.pm

second.pl

Output:

Should have been:

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