When you provide a list when referencing a hash element, perl assumes you are using old perl4-style emulated nested hashes and produces a single hash key like this: $ClubTotal{"DayOfMonth$;$date"}.

Based on looking at the OP's output from Data::Dumper (and on trying it myself), it seems that perl is not adding any sort of field delimiter in the hash key: 

perl -le '$n=0; $h{"foo"=>$n++}=$n for (0..3); print "$_ => $h{$_}" fo
+r (sort keys %h)'
foo0 => 1
foo1 => 2
foo2 => 3
foo3 => 4

[download]
That said, I would agree that presence of the "fat comma" (=>) as part of the hash-key expression looks like a misunderstanding (and/or could be misunderstood by less skilled readers), and is rather ugly as well. Something like simple concatenation or string interpolation would be clearer ($hash{'string'.$num} or $hash{"string$num"}).

In reply to Re^2: Brain muchly befuddled by nested hashes by graff
in thread Brain muchly befuddled by nested hashes by WartHog369

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.