Easier Way?

abitkin has asked for the wisdom of the Perl Monks concerning the following question:

Now, I know one way of doing this, but I would like to see if there is an easier way.

I have some code such that:

my %hash2;
for my $key (sort {$hash1{$b} <=> $hash1{$a}} keys %hash1){
    if (exists($hash2{$hash1{$key}})){
        $hash2{$hash1{$key}}++;
    } else {
        $hash2{$hash1{$key}}=1;
    }
}
[download]

Like I said, I can do it myself, just wondering is there was a easier way (easier being less lines/faster.) I know I loose the key that was put into my %hash1, but that's okay, becuase at this point I no longer need it.

Comment on Easier Way? Download Code

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Re: Easier Way? by Arien (Pilgrim) on Aug 28, 2002 at 21:46 UTC
Counting the number of times a value appears in your hash doesn't have to be more complicated than this: `my %hash2; $hash2{$_}++ for values %hash1;` [download] — Arien	[reply] [d/l]
Re: Easier Way? by Aristotle (Chancellor) on Aug 28, 2002 at 21:54 UTC
Your `if` case isn't necessary, if you increment an nonexistant hash element it is autocreated for you. Also, the `sort` is superfluous since the order in which you look at your keys makes no difference to their count. And lastly, as has been pointed out, since you don't use the keys for anything else than to access the values, just use `values` rather than `keys`. For code, see Arien's post. Makeshifts last the longest.	[reply]
Re: Re: Easier Way? by abitkin (Monk) on Aug 28, 2002 at 22:00 UTC
Wow. Very nice, this gives me a little insight into perl that I had missed. Thanks so much.	[reply]
Re^3: Easier Way? by Aristotle (Chancellor) on Aug 28, 2002 at 22:17 UTC
My pleasure. :-) Makeshifts last the longest.	[reply]
Re: Easier Way? by FoxtrotUniform (Prior) on Aug 28, 2002 at 21:30 UTC
Hmm. `values`? `my %hash2; for my $val (sort values %hash2) { if(exists $hash2{$val}) { $hash2{$val}++; } else { $hash2{$val} = 1; } }` [download] Not much shorter, but a bit easier to read.... `-- F o x t r o t U n i f o r m Found a typo in this node? /msg me The hell with paco, vote for Erudil!`	[reply] [d/l] [select]
Re: Re: Easier Way? by thelenm (Vicar) on Aug 28, 2002 at 21:49 UTC
In fact, the sort and the if test are unnecessary, so we can further reduce the code to this: `my %hash2; $hash2{$_}++ for values %hash1;` [download] -- Mike `-- just,my${.02}`	[reply] [d/l]