in reply to Re^2: Uninitialized value in concatenation (.) or string?
in thread Uninitialized value in concatenation (.) or string?

Check the value of ${$refarray3}[1] for being undef: 
print "it's not defined!\n" unless defined(${$refarray3}[1]);

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If it's undef, it's because of your assignment of undef to $dir back in the while (<FILES>) {...} loop. Perhaps you can use the empty string there instead.

Also, if you want $matchedfiles[$c] to be list of files, you need to use this syntax: 

push(@{$matchedfiles[$c]}, [...]);

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This makes $matchedfiles[$c] an array ref (i.e. @matchedfiles is an array of array refs.)

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Re^4: Uninitialized value in concatenation (.) or string?
by jbush82 (Novice) on May 09, 2008 at 17:22 UTC
    I'm confused as to why $dir is undefined. The line:

    print "$file is in the directory $dir\n";

    Produces the output that I'm looking for, the file and the directory it is in:
    Ascent.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Autumn.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Azul.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Bliss.bmp is in the directory C:\WINDOWS\Web\Wallpaper
Crystal.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Follow.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Friend.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Home.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Moon flower.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Peace.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Power.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Purple flower.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Radiance.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Red moon desert.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Ripple.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Stonehenge.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Tulips.jpg is in the directory C:\WINDOWS\Web\Wallpaper
Vortec space.jpg is in the directory C:\WINDOWS\Web\Wallpaper

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    Which is just the listing of the files and what directory they are in. If it is successfully printing output, would that not indicate that it is defined?

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      The print statement will still work - an undef value will print as the empty string.

      Sorry, I mistook line 71 for a similar looking line (the one in the foreach $intersect (@uniq) loop.)

      If this is where you problem is: 

      my $refarray3 = $matchedfiles[5];
print "File: ${$refarray3}[0] in directory ${$refarray3}[1]\n";

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      then maybe $refarray3 is undef. How many elements are there in the @matchedfiles array?
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        I'm trying to pass two elements per row. The filename and the MD5 value.

        print "\n\n";
my $refarray3 = $matchedfiles[5];
print "it's not defined!\n" unless defined(${$refarray3}[0]);
print "it's not defined!\n" unless defined(${$refarray3}[1]);
print "File: ${$refarray3}[0] in directory ${$refarray3}[1]\n";

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        Both of the elemnts in the 5th row of the matchedfiles array show the output of not being defined. It seems as if nothing is being passed to the array, when back on line 63 I have the following:

        push(@{$matchedfiles[$c]}, [${$refarray1}[0], ${$refarray1}[1]]); I've updated the main post with the latest code.
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