I guess this is more or less what you're looking for (demonstrated under the Perl debugger): 
  DB<14> @array = (['X1','X2','X3','X4' ], ,['','key', ''], ['key', ''
+, '']);

  DB<15> x \@array
0  ARRAY(0x600501580)
   0  ARRAY(0x6005d2818)
      0  'X1'
      1  'X2'
      2  'X3'
      3  'X4'
   1  ARRAY(0x6005015f8)
      0  ''
      1  'key'
      2  ''
   2  ARRAY(0x6004fa8c0)
      0  'key'
      1  ''
      2  ''

  DB<16>  for my $subarrayref ( @array ) {  $subarrayref = [ grep leng
+th $_,  @$subarrayref] }

  DB<17> x \@array
0  ARRAY(0x600501580)
   0  ARRAY(0x6005d2d70)
      0  'X1'
      1  'X2'
      2  'X3'
      3  'X4'
   1  ARRAY(0x600500e60)
      0  'key'
   2  ARRAY(0x600635c28)
      0  'key'

[download]

In reply to Re: Removing empty elements from multi-dimensional array by Laurent_R
in thread Removing empty elements from multi-dimensional array by OldMonkRum

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.