I agree with my learned brethren that a module such as Text::CSV_XS would be the best practice way to go here. However, for an example of how to do this otherwise and assuming that you really do want undef when you say "null", here is an SSCCE.

use strict;
use warnings;

use Test::More tests => 2;

my $have = '1,,3,4,,,';
my @want = (1, undef, 3, 4, undef, undef, undef);

my @try = map { length ($_) ? $_ : undef } split (',', $have, -1);

is_deeply \@try, \@want, 'Array is correct';

# Your criterion
my $count = 0;
foreach (@try) {
    ++$count;
}

is $count, 7, 'Count is correct';

[download]

In reply to Re: But I want null values in my array by hippo
in thread But I want null values in my array by sidmuchrock

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.