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    <p><strong>Errors:</strong></p> <pre><code>for($i=0;$i&lt;=5;$i++) $values{$proposal[$i]}[$i]++; for($i=$proposal[1];$i&lt;=$proposal[2];$i++) $values{$i}[6]++; </code></pre> <p>Perl does not support bare loop/conditional blocks. Or rather, <a href="http://perldoc.perl.org/perlsyn.html#Statement-Modifiers" rel="nofollow noreferrer">it does</a>, but not like this. This may work in PHP, but not in Perl. You will want to enclose these in blocks:</p> <pre><code>for($i=0;$i&lt;=5;$i++) { $values{$proposal[$i]}[$i]++; } for($i=$proposal[1];$i&lt;=$proposal[2];$i++) { $values{$i}[6]++; } </code></pre> <hr> <pre><code>$values{$proposal[$i]}[$i]++; </code></pre> <p>Since hashes in Perl can only fit scalar data types in them, in order to store an entire array inside of a hash, we're going to have to do it by reference. Here's a quick tutorial on array references:</p> <pre><code>my $arr_ref = []; # empty array reference my $arr_ref = [ 1, 2, 'foo', ]; # initialize with values my $arr_ref = \@arr; # reference an existing array; # does not make copy, but provides a # read-write handle to the array $arr_ref-&gt;[0]; # index the first (index 0) element of the array @{$arr_ref}[ 0 .. 4 ]; # index elements number one through five (0-4) of the array # through what's called an "array slice" </code></pre> <p>What your code above does is pull the value at hash key <code>$proposal[$i]</code> out of the hash <code>%values</code>, then use it (a scalar) as an array (it is not an array).</p> <p>As I said before, you can use it as an array <em>reference</em> but not an array:</p> <pre><code> # v-- note the arrow $values{$proposal[$i]}-&gt;[$i]++; </code></pre> <p><strong>Suggestions:</strong></p> <ul> <li><p>Writing <code>my $foo; for ($foo = 0; $foo &lt;= 5; $foo++)</code> is more easily written as "<code>for my $foo (0 .. 5)</code>" or "<code>foreach my $foo (0 .. 5)</code>". This is, in essence how most people do it. Of note is that <code>for</code> and <code>foreach</code> are interchangeable&ndash;it's a matter of preference and legibility.</p></li> <li><p>Please, for legibility's sake, indent your code with more than one space. A good rule of thumb is four spaces, or a tab. St. Larry Wall was thinking of languages people speak and write when he designed Perl.</p></li> <li><p>I'd recommend researching the proper (proper, here, meaning most efficient) way to write <code>for</code> loops. There are a few habits that can result in faster programs overall if they have a lot of long <code>for</code> loops. For instance:</p> <ul> <li><code>++$foo</code> is more efficient than <code>$foo++</code>. This stems from the internals: <ul> <li><code>$foo++</code> increments the variable, subtracts 1 from it, then returns the result, whereas</li> <li><code>++$foo</code> increments the variable and returns it. Fewer operations = faster.</li> </ul></li> <li>A less-than-or-equals comparison is less efficient than a plain less-than comparison. Again, this is due to the number of operations you computer has to perform. <code>for ($x=0; $x&lt;=5; ++$x)</code> is better-written as <code>for ($x=0; $x&lt;6; ++$x)</code>.</li> </ul></li> <li><p>Perl has some wonderful loop controls. Some, like <code>map</code>, are very powerful.</p></li> </ul>
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    1. CO$values{$proposal[$i]}[$i] is perfectly fine. You only need the -> arrow to dereference a scalar at the beginning. Eg: my $arr_ref=[ { a=>'f', b=>'g'}, { c=>'h', d=>'i' }]; print $arr_ref->[0]{b};
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    2. CO@DougWebb - You're perfectly right; Perl does compensate for the lack of a `->` in the expression, even in `use strict`. I'll leave it as-is to give the OP a sense of what is going on as far as the data structures go.
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    3. COI've got a pretty good idea of how the structures work now. My code actually works, and looks quite a bit cleaner as well! I'm still figuring out when Perl does and doesn't do things automatically, but this is a good push in the right direction. Thanks all!
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