Just to elaborate a bit more on this, consider the code:

my @PP = ("foo", "bar", "baz");
my @OO = ("AAA", "bar", "CCC");

$PP[1][0] = "foobar";
[download]

What happens is that this does not modify the @PP array, instead it uses the value of $PP[1] as an array reference which points to the global(/package) variable @bar. To make this a bit clearer:

#!/usr/bin/perl -l

my @PP = ("foo", "bar", "baz");
my @OO = ("AAA", "bar", "CCC");

$PP[1][0] = "foobar";

print "\@PP: " . join(", ", @PP);
print "\@OO: " . join(", ", @OO);
print "\@bar: " . join(", ", @::bar);
[download]

Output:

@PP: foo, bar, baz
@OO: AAA, bar, CCC
@bar: foobar

The '@PP' and '@OO' array are unmodified; the '@bar' array however was created.

With use strict; you get the error: Can't use string ("bar") as an ARRAY ref while "strict refs" in use

---

---

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! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

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:
	&		&
	<		&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.