The only one that is syntactically valid is the second one, however, I don't believe that it is doing what you are expecting. Since the parens denote precedence, what Perl reads it as is: 

my %sham =  (
                1 => "j",
                2 => "b",
                1 => "p",
                2 => "b",
        );

[download]

When assigning to hashes, later insertions with the same key end up replacing any earlier entries with the same key, leaving you with:

my %sham =  (
                1 => "p",
                2 => "b",
        );

[download]

This can be shown with the use of Data::Dumper or the like. I think what you are intending is:

my @sham =  (               # note the sigil
               {
                1 => "j",
                2 => "b",
               },
               {
                1 => "p",
                2 => "b",
               },
        );

[download]

Data::Dumper (and any similar module) is a useful tool for visualizing nested data structures.

--MidLifeXis

In reply to Re: Difference in Hash Declaration by MidLifeXis
in thread Difference in Hash Declaration by perl@1983

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.