Hi Monks, I am having a nested hash with depth ranging from 4-5 like 
 VAR1 = {A => { 
           LEVEL1 => {
              LEVEL1_2 => {
                  LEVEL1_2_3 => {
                     VAL > 'somevalue'
                    }
               }
            }
         }

I am using a if statment with defined in a loop, 
for (my i = 0; i< 3; i++) {
  if (defined $hash->{A}->{LEVEL2}->{LEVEL2_2) { 
     # do something
  } elsif (defined $hash->{A}->{LEVEL1}->{LEVEL1_2) {
     #do something
  }
}

[download]
For first loop iteration if returns false, but at the same time it creates an empty slot in a hash with undef value. (I checked it using Data::Dumper in loop to print hash.) so when for loop iterates for 2nd time, empty slot created matches if statment instead of elsif, and execute wrong set of instructions. I am not able to understand why an empty slot is created. somewhere i read there is a issue with use exists with nested (->) structure. Am I hiting the same issue ? I tried without defined, and faced same issue, so unable to understand.

In reply to usage of if on nested hash creating empty slot for non existing value by rakeshrocks

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.