Traversing a hash in order - perl

Question

I would like to traverse the HASH but one by one. Not in Random ways. Any idea. For example i have hash file something like this...
our %HASH = (
'rajesh:1700' => Bangalore,
'rajesh:1730' => Delhi,
'rajesh:1770' => Ranchi,
'rajesh:1780' => Mumbai,
'rajesh:1800' => MYCITY,
'rajesh:1810' => XCF,
);
and it should print in same fashion. I tried with following but failed. Any ideas?
while ( my $gPort = each %HASH)
{
print "$gPort\n";
}
for my $gPort ( keys %HASH )
{
print "$gPort\n";
}

Answer 1

Given the keys in your question, a simple change to the sort comparator will give your desired output.
for my $gPort (sort keys %HASH) {
print "$gPort => $HASH{$gPort}\n";
}
Note: the code above assumes all numbers in keys will occur at the same position and have the same length. For instance, a rajesh:001775 key will come out first rather than between 1770 and 1780.

Answer 2

You could sort and print out a hash, ordering by VALUE (not keys).
for my $gPort (sort { $HASH{$a} <=> $HASH{$b} } keys %HASH) {
print "$gPort => $HASH{$gPort}\n";
}

Answer 3

Take a look at Data::Dumper. In particular, if you set $Data::Dumper::Sortkeys, then you would get the dump in sorted order.
As an example:
use Data::Dumper;
$Data::Dumper::Sortkeys = 1;
my %some_hash;
# code to populate hash
[ . . . ]
print Dumper(\%some_hash);
Of course, this would work only if you want to plainly dump the hash. If you want the printing to be done in some other format, you would want to just sort the keys and print, like
foreach my $key (sort keys %some_hash) {
print "[KEY]: $key; [VAL]: $some_hash{$key}\n";
}

Answer 4

If you wish to preserve the insert-order of your elements in your hash then Tie::IxHash may be the tool for you. It's usage is very simple:
Showing you simple example:
use Tie::IxHash;
tie my %days_in => 'Tie::IxHash',
January => 31,
February => 28,
March => 31,
April => 30,
May => 31,
June => 30,
July => 31,
August => 31,
September => 30,
October => 31,
November => 30,
December => 31;
print join(" ", keys %days_in), "\n";
# prints: January February March April May June July August
# September October November December