short answer

print this on a t-shirt:

and wear it at work. ;-)

long answer

$PP[1][2]=3 is a shorter notation for $PP[1]->[2] = 3

so with

$PP[1] == $OO[1] == 1

what you are effectively doing is

1->[2] = 3

which is just populating @1

debugger-demo perl -de0 

  DB<46> 1->[2] = 3

  DB<47> x @1
0  undef
1  undef
2  3
  DB<48>

[download]

For good reasons that's forbidden under strict

  DB<45> use strict; my @PP; $PP[1]=1; $PP[1][2] = 3
Can't use string ("1") as an ARRAY ref while "strict refs" in use at (
+eval 66) ...

[download]

> FWIW, assigning the numbers to the arrays in separate lines makes no difference.

Well I hope it's now clearer why...

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

In reply to Re^3: Array weirdness by LanX
in thread Array wierdness by lgp

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.