My issue is that the perl script (as I have done it so far) created empty branches when I try to check some branches on existence.

I am using multydimentional hashes: found it as the best way for information that I need to handle. Saing multidimentional I means hash of hashes ... So, I have 

$hsh{k1}{k2}{k3}{k4}=v1;
$hsh{k1}{k9}{k3}{k33}=v2;
....

[download]

In some point I need to check some 'set of keys' on existence in the hash. So, I check: 

if ( $hsh{ch1}{ch2}{ch3} ) {  ...something... }

[download]

And, suddenly I've realized, that such check creates the intermediate branches to access the final one for checking!

So, if there is no $hsh{ch1} before the check, it will be created to access the key 'ch2', which will be created to access the 'ch3'

QUESTION: Is there a way to avoid such aromatic creation ????

Logically, I would expect the Perl to get FALSE as soon as any key is not exist in the hash, but it is not happening!

Sure I could do: 

if ( $hsh{ch1} && $hsh{ch1}{ch2} && $hsh{ch1}{ch2}{ch3} ) 
{...}

[download]

but it is so annoying, especially when I have many hashes with 7- 10 keys!

I have creates some function to check a hash 'reasonably', sending hash reference and array of keys to be checked, and it works fine, but it is slows down the processing visibly.

Here is an example of what I am talking about: 

  DB<4> $h{a}{b}=[1,2]; $h{a}{c}=[3,4]  #hash with two elements (array
+s) and in 2 levels

  DB<5> use Data::Dumper  #good way to display 

  DB<6> p Dumper\($a,%h)
$VAR1 = \undef;
$VAR2 = {
          'a' => {
                   'c' => [
                            3,
                            4
                          ],
                   'b' => [
                            1,
                            2
                          ]
                 }
        };

  DB<7> p 'da' if !$h{p}{m}  #checking for an existent keys and elemen
+t
da
  DB<8> p Dumper\($a,%h)
$VAR1 = \undef;
$VAR2 = {
          'p' => {},            # <<== created one !!!
          'a' => {
                   'c' => [
                            3,
                            4
                          ],
                   'b' => [
                            1,
                            2
                          ]
                 }
        };

  DB<9> delete $h{p}

[download]

Once again: Is there a way to avoid such behavior without creating additional function?

Thanks!

In reply to perl: restrict perl from automaticaly creating a hash branches on check by alex5161

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.