key1=val1&key2=val2&key3&key4&key5&key6=val6
[download]

-- Randal L. Schwartz, Perl hacker

Good point.

But look, it's great to point out the module (which I did), but is that a learning experience? Certainly CGI should be used for handling CGI, but no one answered this poor anon_monk's more general question, which was about handling lists and assigning values to hashes (and sadly, my answer assumed that we were feeding valid pairs in, something I would now know to change). Thus, this poor monk still has no idea how to write Perl to do this when there isn't a module involved. And so we'll have this really great use of modules strung together with the Perl equivalent of baby talk. This is good if the monk is going to immediately put something into production... but is this good for the personal growth of the monk?

"The answer which no one is willing to give you is this"

And the reason that no-one is willing to give this answer is that it has fundamental flaws.

As well as the example that merlyn gives, your code also breaks on a query string like this:

key1=val1&key2=val2a&key2=val2b
[download]

Update: D'oh! Corrected example so the values are actually different! Thanks merlyn.

"Perl makes the fun jobs fun
and the boring jobs bearable" - me

Well, not that one because your two values are the same. {grin}

-- Randal L. Schwartz, Perl hacker

Um, even if the values are different, it doesn't really break. It just overwrites the first value for key2 with the second listed value for this. Shouldn't keys be unique if we expect them to actually be keys? How does CGI handle this exception?

It's quite common (and useful) to have multiple values associated with one name. These aren't keys in the same sense that unique identifiers are in a database. Considering the following:

You're creating a Web page where people can sign up for mailing lists on their favorite sports. You have the following HTML:

<input type="checkbox" name="football" value="football">
<input type="checkbox" name="soccer" value="soccer">
<input type="checkbox" name="tiddly winks" value="tiddly winks">
[download]

In your code, you check for each of those values and subscribe the person to the mailing list appropriately. However, as time goes on, your site becomes wildly popular and you are looking at your IPO. You include more and more sports, but your scripts are becoming difficult to maintain because you have to test for each and every sport individually. Instead, change your HTML to the following:

<input type="checkbox" name="sports" value="football">
<input type="checkbox" name="sports" value="soccer">
<input type="checkbox" name="sports" value="tiddly winks">
[download]

Your query string will resemble the following (if they check both football and tiddly winks):

sports=football&sports=tiddly%20winks
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In your script, you'd have something like the following:

my @sports = $q->param('sports');
foreach my $sport ( @sports ) {
    # subscribe them to the list
}
[download]

That is much simpler than having separate names for each sports. Programmatically, it's the way to go.

Cheers,
Ovid

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