perl hash of arrays

Question

I am trying to access elements of an array which is part of a hash.

for my $idx ( 0 .. $#vss ) {
    push (@{$vsnhash->{$vss[$idx]}}, $vsports[$idx]);
}
print Dumper(\%$vsnhash);

($VAR1 = {
      'name2' => [
                   '8001',
                   '8002'
                 ],
      'name1' => [
                   '8000'
                 ]
    };

I an able to access the keys with a foreach loop:

foreach my $key ( keys %$vsnhash ) {
print "$key\n";
}

How do I access the array of port numbers ('8001' , '8002') within the hash?
Thank you for the help!

Eugene Yarmash · Accepted Answer · 2011-10-12 14:54:37Z

5

while (my ($k, $v) = each %$vsnhash) {
    print "$k: @$v\n";
}

answered Oct 12, 2011 at 14:54

Eugene Yarmash

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2 Comments

FailedDev Over a year ago

Wow. I have no idea how this works but it's cool to learn new stuff :)

musiKk Over a year ago

@FailedDev: It's fairly simple actually. each is like keys but gives you key and value at the same time. @$v is short for @{$v} and dereferences an array reference.

FailedDev · Accepted Answer · 2011-10-12 15:06:32Z

1

foreach my $key ( keys %$vsnhash ) {
   print "$key\n";
   foreach my $port (@{$vsnhash->{key}}){
      print "Port $port\n";
   }
}

edited Oct 12, 2011 at 15:06

answered Oct 12, 2011 at 14:50

FailedDev

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1 Comment

Eric Over a year ago

Basically correct, but you've got some syntax errors. Should be: foreach my $port (@{$vsnhash->{$key}}){ instead of foreach my $port (@{$vsnhash{key}}){

David W. · Accepted Answer · 2011-10-12 16:35:02Z

1

$vsnhash{name2}->[0];   #8001
$vsnhash{name2}->[1];   #8002
$vsnhash{name1}->[0];   #8000

Code wise:

foreach my $key (sort keys %vsnhash) {
   foreach my $index (0..$#{$key}) {
      print "\$vsnhash{$key}->[$index] = " . $vsnhash{$key}->[$index] . "\n";
   }
}

The $#{$key} means the last entry in the array @{$key}. Remember that $key is a reference to an array while @{$key} is the array itself.

answered Oct 12, 2011 at 16:35

David W.

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