Use of uninitialized value in tie array

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks!

I am trying to get rid of this warning and my question is how to avoid this:

Use of uninitialized value $array[0] in pattern match (m//) at ...

Here is the code I am trying to fix to avoid getting the uninitialized warnings:

...

my $dir_txt_files = "stuff/";

tie my @array, 'Tie::File', $dir_text_files or die "Could not open fil
+e '$dir_text_files' $!";

 
 unshift @array, 'NAME, ADDRESS, ZIPCODE' unless $array[0] =~ /^[a-zA-
+Z]/;

 # Remove any blank lines.
 @array = grep /\S/, @array;

 untie @array;

....
[download]

Thanks for looking!

Comment on Use of uninitialized value in tie array Select or Download Code

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Re: Use of uninitialized value in tie array by Corion (Patriarch) on Apr 01, 2016 at 13:33 UTC
Maybe the file is empty? Have you inspected how many elements there are in `@array`? On further inspection of your source code, the variable `$dir_txt_files` is named in a way that suggests that it is not a filename. This is furthered by you assigning it the value `stuff/`. But Tie::File wants a filename, not something else. Maybe you want to use glob or File::Find to find files?	[reply] [d/l] [select]
Re^2: Use of uninitialized value in tie array by Anonymous Monk on Apr 01, 2016 at 13:48 UTC
Its a file name. Yes, the file could be empty and thats where the issue occurs. Trying to figure it out a way to prevent it and how is the question.	[reply]
Re^3: Use of uninitialized value in tie array by Corion (Patriarch) on Apr 01, 2016 at 13:55 UTC
`scalar @array` gives you the number of elements in an array. `if( @array ){` will also only be true if the array contains at least one element.	[reply] [d/l] [select]
Re^4: Use of uninitialized value in tie array by Anonymous Monk on Apr 01, 2016 at 16:24 UTC
Re: Use of uninitialized value in tie array by Anonymous Monk on Apr 02, 2016 at 02:49 UTC
How about 'if (! defined $array[0])'?	[reply]