Re^2: Use of uninitialized value

As requested
More code here:


  foreach (@SQL_queries) {

    my $Results = $_;
    
    my $sth_atl = $dbh->prepare($Results) or die "Couldn't prepare que
+ry: ".$dbh->errstr;
    $sth_atl->execute() or die "Couldn't execute query: ".$sth_atl->er
+rstr;
    
    my $cols_for_row;
    
     


    while ($cols_for_row = $sth_atl->fetchrow_arrayref) {

      print OUTFILE "England\t";
      print OUTFILE join("\t",@$cols_for_row),"\n";

      my $last_element = @$cols_for_row[-1];

      my $indicator =  @$cols_for_row[-2];


      my $numerator;
      my $denominator;
      

      if ($indicator eq "SH"){
    $numerator = $last_element;
      }
      elsif ($indicator eq "SL"){
    $denominator = $last_element;
      }
      else {
    print "\nError: There has been an unexpected string within the sec
+ond to last element of the array\n";
      }


    print "\n>>>>>numerator>>>>>>>>>>>> $numerator\n";  #  Works here
    print "\n>>>>>>denominator>>>>>>>>>>> $denominator\n"; # Works her
+e


      if (($numerator > 0) && ($denominator > 0)){
    
    print "\n>>>>>numerator>>>>>>>>>>>> $numerator\n";  #  Does not wo
+rk here
    print "\n>>>>>>denominator>>>>>>>>>>> $denominator\n"; # Does not 
+work here

    my $expected_ratio_figure = ($numerator)/($denominator);
    print OUTFILE "\n\nThe expected ratio figure:\t";
    print OUTFILE "$expected_ratio_figure\n\n";
      }
    }
  }
[download]

Comment on Re^2: Use of uninitialized value Download Code

Replies are listed 'Best First'.
Re^3: Use of uninitialized value by Ratazong (Monsignor) on Nov 23, 2010 at 11:31 UTC
`my $numerator; my $denominator; if ($indicator eq "SH") { $numerator = $last_element; } elsif ($indicator eq "SL"){ $denominator = $last_element; } else { ... } if (($numerator > 0) && ($denominator > 0)){ ...` [download] The first time you execute the loop, `$numerator` or `$denominator` may get initialized, but never both. Therefore you get the error message `Use of uninitialized value in numeric gt (>) at New_program.pl line 535`.	[reply] [d/l] [select]
Re^4: Use of uninitialized value by Anonymous Monk on Nov 23, 2010 at 11:39 UTC
I think you're right, but that would not explain his comments works here/ does not work here, the error would be the same at both points	[reply]
Re^5: Use of uninitialized value by marto (Cardinal) on Nov 23, 2010 at 11:49 UTC
I wouldn't bother wasting your time trying to find an explanation for their comments, they've clearly spent no time debugging the problem or actually reading their code, why would the comments have to make sense?	[reply]
Re^6: Use of uninitialized value by Anonymous Monk on Nov 23, 2010 at 11:59 UTC
Re^7: Use of uninitialized value by Boldra (Curate) on Nov 23, 2010 at 14:58 UTC
Re^5: Use of uninitialized value by Ratazong (Monsignor) on Nov 23, 2010 at 13:22 UTC
`if (($numerator > 0) && ($denominator > 0)){ print "..."; # (print) do +es not work here` [download] The condition will never be true, as at least one of the variables is `undef`. Therefore the `print` will never be executed. I assume that this is the reason for the comment `does not work here`.	[reply] [d/l] [select]
Re^3: Use of uninitialized value by chromatic (Archbishop) on Nov 23, 2010 at 19:19 UTC
`my $numerator; my $denominator;` [download] Here both `$numerator` and `$denominator` contain `undef`. `if ($indicator eq "SH"){ $numerator = $last_element; }` [download] If that branch is true, `$numerator` will contain the value of `$last_element`, which may be `undef`. `$denominator` will still contain `undef`. `elsif ($indicator eq "SL"){ $denominator = $last_element; }` [download] If that branch is true (and it will only be true if the first branch is false, in which case `$numerator` will still contain `undef`), `$denominator` will contain the value of `$last_element`, which may be `undef`. `else { print "\nError: There has been an unexpected string within the sec +ond to last element of the array\n"; }` [download] If this branch is true, both `$numerator` and `$denominator` contain `undef`. At this point, at least one of those two variables does contain `undef`. Both may.	[reply] [d/l] [select]
Re^3: Use of uninitialized value by cjb (Friar) on Nov 23, 2010 at 11:41 UTC
`my $numerator; my $denominator; if ($indicator eq "SH"){ $numerator = $last_element; } elsif ($indicator eq "SL"){ $denominator = $last_element; } else { print "\nError: There has been an unexpected string within + the second to last element of the array\n"; }` [download] You only ever initialise $numerator or $denominator ~~on the first run through.~~ Something like `my $numerator = 0; my $denominator = 0;` [download] might work, if 0 is a suitable default value for you.	[reply] [d/l] [select]
Re^4: Use of uninitialized value by Anonymous Monk on Nov 23, 2010 at 11:59 UTC
No, it's initialized to undef in every iteration of the loop.	[reply]
Re^5: Use of uninitialized value by cjb (Friar) on Nov 23, 2010 at 12:20 UTC
You're right, my bad. ~~strike~~ time it is then.	[reply]
Re^3: Use of uninitialized value by Anonymous Monk on Nov 23, 2010 at 11:36 UTC
As requested More code here: No, that is not what was requested. There is no way the code you posted could create the error message you get, at the point you say you get it. Its impossible.	[reply]


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