Simple Hash Question

[BlenderHead]

Hello World:

I have the following code written to generate a hash:

my $count = 1;
my @array = ('A','B','C');
my %hash = ();

for my $i (@array) 
{
  # set key AND initialize by $count as value of key.

  $hash{$i} = $count;      
  $count++;
}

Now, what I want to do is sort the hash by values and print it out, but my print loop isnt working right. I can get the values out okay, but the keys are not working to print.

Here's what I have.

for my $key ( sort {$hash{$a} <=> $hash{$b} } keys %hash )
{
     print " MIRACLE_HAPPENS is equal to $hash{$key}.<br>\n";
}

As you can see - it wont print the key name. It'll only print the sorted values. Where it says "MIRACLE HAPPENS" is where I need it to print the key name. Can anyone show me how to do that please?

Thanks!

BH

[kennethk]

The keys of the hash are what you want to print out. If I understand your difficulty, all you need to do to get your desired result it to use $key in place of $hash{$key} in your print statement, i.e.

#!/usr/bin/perl
use strict; 
use warnings;
my $count = 1;
my @array = ('A','B','C');
my %hash = ();

for my $i (@array) 
{
  # set key AND initialize by $count as value of key.

  $hash{$i} = $count;      
  $count++;
}
for my $key ( sort {$hash{$a} <=> $hash{$b} } keys %hash )
{
     print " MIRACLE_HAPPENS is equal to $key.<br>\n";
}

[BioLion]

Not sure if I am missing something, but if you want to print the key, print the key:

for my $key ( sort {$hash{$a} <=> $hash{$b} } keys %hash )
{
     print " MIRACLE_HAPPENS is equal to key : \'$key\' and value : \'
+$hash{$key}\'.\n";
}

perldoc may be a good resource for further reading. HTH.

[johngg]

A minor point but you don't have to escape single-quotes in a double-quoted string.

$ cat xxx
$key = 'abc';
print "Key is: '$key'\n";
$ perl xxx
Key is: 'abc'
$

I hope this is useful.

[BlenderHead]

Heh... Am sorry guys...

Thank you for your help. :) It solved the problem.

As per reading the manual - I AM reading the manual... I wouldn't be here if I weren't... ;-)

[ikegami]

If you're trying to count the number of occurrences of each array element, what you want is:

my @array = qw( a b r a c a d a b r a );

my %counts;
++$counts{$_} for @array;

for my $key ( sort { {$counts{$b} <=> $counts{$a} } keys %counts ) {
    print("$key: $counts{$key}\n");
}