Hi Monks,

A line of code from a perl script I have inherited is giving me the wonderful warning: 

Use of uninitialized value in string ne ...

[download]
The line looks like this: 
 if ($this_loc ne $last_loc) {

[download]
Searhing perlmonks shows quite clearly that one of the two variable is undefined. So I feel well equipted to solve this problem.

Since $this_loc is read from a database and $last_loc is simply the value of the last $this_loc I deduce that its $this_loc which is getting undefined while being read from the database.

So my trival question is: If you define the variable at the start of the code: 

my $this_loc = -111;

[download]
..as they have done at the start of the script.. how can the act of updating the contents of the value clobber this variable? 
 $this_loc = $rowDivData->{LOCATION_ID};

[download]
Would it not just contain a null string if nothing was found in the database - but still exist? 
 ___
/\__\ Creative Object World (COW)
\/__/ www.wolispace.com/cow

[download]

In reply to A bit more clarity on uninitialized value in string ne by wolis

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.