[Linux-disciples] Converting an array to a hash

[Stephen R Laniel]

On Wed, Oct 06, 2004 at 01:20:10PM -0400, Chung-chieh Shan wrote:
> You can assign multiple entries into a hash at the same time:
> 
>     @hash{1,2,3} = (4,5,6);
> 
> If the right-hand-side list is shorter than the left-hand-side, then
> undef is used.  Hence you can make a hash whose keys are words and
> values are undef:
> 
>     my %wordsHash;
>     @wordsHash{m/([A-Za-z]+)/g} = () while <>;

You guys have convinced me that it doesn't much matter. I
actually think the code ends up being more literate in any
case if I use an array *and* a hash.

My needs are actually a bit more complicated than I thought.
I ended up deciding to turn the word list into a frequency
distribution of words, so that the meat looks like

%wordsHash = ();
File::find( some stuff, wanted => \&wanted );

and the meat of wanted() is

@words = m/([A-Za-z]+)/g;
foreach my $word (@words) {
	%wordsHash{$word}++;
}

I doubt there's a quicker way to do this. And in any case,
@word only ever contains the words from a single file
(whereas %wordsHash contains all the words from all the
files that the wanted() function hit), so @words will never
be all that large. Not enough to worry about.

Thanks for all your input.

-- 
``I am all about the delivery of *justice* to
  parking, people. That is all.''
 -Jon Sung, 27 September 2004

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