You probably mean undefined elements, NULL is a c-thing. One way to create an array with undefined elements is to use indexes and then skip a few. With grep -ing for defined elements, you can weed the undefined elements, as shown in the example below.

As mentioned, an empty array is not the same as an undefined array, and "0" is defined, so you don't want to skip it. 

#!/usr/bin/perl
my (@ar1, @ar2);

$ar1[0] = 1;
$ar1[1] = 0; # a defined element, not NULL
$ar1[7] = 9; # skip, leaving 2..6 undefined

# dump array 1
print("\@ar1:\n");
for my $i (0..$#ar1) {
   print("   $i : $ar1[$i]\n");
}

# weed the undefined elements
@ar2 = grep { defined $_ } @ar1;

print("\@ar2:\n");
for my $i (0..$#ar2) {
   print("   $i : $ar2[$i]\n");
}

[download]

In reply to Re: any built in function to take out null arrays elements? by lyklev
in thread any built in function to take out null arrays elements? by adrive

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.