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In my Perl program, I am reading an email by decoding it, splitting it into an array. In the snippet below, I am reading the elements and appending it until I find 'Email' or 'Phone' or 'GoToAssist'.

75  while(!($plain[$j] =~ /[Email|Phone|GoToAssist]/)){     
76      $plain[$x] .= " " . $plain[$j];
77      $j++;
78  }

However, I am getting the following error:

Use of uninitialized value in concatenation (.) or string at test.pl line 76, <GEN0> line 921.
Use of uninitialized value in pattern match (m//) at test.pl line 77, <GEN0> line 921.

The code was working properly previously, I have hardly changed anything. I am wondering what went wrong.

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5
  • Have you checked if your data has changed? Commented Jul 10, 2012 at 14:11
  • Yes, I checked. Two elements were changed. But I had removed them using regex. It doesnt work with the previous data either. Commented Jul 10, 2012 at 14:12
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    If it was working previously and data JUST changed - it has to be that the regex is not working as expected in removing faulty parts of the changed data. I mean, I have no empirical evidence...but WHAT ELSE could it be, haha. Could we get and example entry? Commented Jul 10, 2012 at 14:15
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    $plain[$j] is undefined. We cannot help you to fix this unless you show your complete code. Also the regex /[Email|Phone|GoToAssist]/ doesn't do what you intend. It uses a character class that matches any of the characters A E G P T a e h i l m n o s t |. You want just /Email|Phone|GoToAssist/. Commented Jul 10, 2012 at 14:22
  • Here is the code gist.github.com/3083791. It is working now for some reason! I wonder whats going on! Commented Jul 10, 2012 at 14:56

2 Answers 2

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3

Its not an error, its a warning.

You are getting this warning because $plain[$j] is undefined.

You can use following code to check if plain[$j] is defined or not before appending:

while(!($plain[$j] =~ /[Email|Phone|GoToAssist]/)){     
     if(defined $plain[$j]){
         $plain[$x] .= "&nbsp;" . $plain[$j];
         $j++;
     }
 }

If this doesn't help, do share some more code.

And as @Borodin pointed out, your regex is not doing what you probably want. But this is not related to your question.

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3 Comments

Well, that actually worked! But when I commented these changes, it did work again! I dont know whats going on to be honest. You can find my code here: gist.github.com/3083791 You can see the commented statements line # 77 onwards. Thanks.
@rad are you sure you have used the same data which was giving error earlier?
@rad strange...anyways you can keep if-defined check to prevent future warnings....the string being appended cannot be undefined
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$plain[$j] is undef. Add some print statements to find out if $j is what you expect it to be. If it's wrong, then find out why it ends up with the wrong value. It it's right, find out why $plain[$j] ends up with the wrong value.

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4 Comments

I tried that. It gave me the same errors followed by a million &nbsp;'s. Sorry.
print "plain[x] = '" . ( $plain[$x] || '' ) . "'\n" ; print "plain[y] = '" . ( $plain[$y] || '' ) . "'\n" ;
I am getting plain[j] = '' and plain[x] has about a thousand &nbsp;'s
then $plain[$j] and $plain[$x] are not defined - look into the code which populates them

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