Here is one way to generate that sort of warning message (there are many other ways): 
my @array=qw/foo bar/;
$array[3] = "baz";

foo1( @array );  # $array[2] is undefined

[download]

One way to avoid the warning would be: 

   for my $param (grep {defined} @_) {
      for my $val ( split /\n/, $param ) {
         print "The value is: $val\n";  # or whatever you want to do
      }
   }

[download]
(I took the liberty of eliminating unnecessary variables, and localizing the scope of needed variables a little more tightly.)

The other methods suggested above would also work, I expect. There might be reasons for preferring one approach over the other, depending on the rest of your application.

In reply to Re: Wierd error message by graff
in thread Wierd error message by herby1620

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.