Uninitialized value in concatenation

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

I am having problems with what I thought was a pretty simple script. The errors I get are

Use of uninitialized value in concatenation (.) or string at ./fund.pl
+ line 25, <STDIN> line 1.
Use of uninitialized value in concatenation (.) or string at ./fund.pl
+ line 28, <STDIN> line 1.
Use of uninitialized value in concatenation (.) or string at ./fund.pl
+ line 32, <STDIN> line 1.
Use of uninitialized value in concatenation (.) or string at ./fund.pl
+ line 32, <STDIN> line 1.
Use of uninitialized value in transliteration (tr///) at ./fund.pl lin
+e 47, <STDIN> line 9535.
Use of uninitialized value in concatenation (.) or string at ./fund.pl
+ line 48, <STDIN> line 9535.
[download]

I am unsure what is causing this error and any help would be appreciated. The script is below.

#!/usr/bin/perl -w
###### usage: cat inputfile | abiglobal.pl



$i=0;
while ($_ = <STDIN>) {

if(/(FUND ACTIVITY REPORT)/ ) {

    $input=$_;
    chop($input);
    $fundcode=substr($input,0,5);
    $fundcode=~ s/ //g;
    $input=~ tr/\"//;
    $input=~ tr/\'//;
#    $input=~ tr/,/\t/;
    $input=~s/REPORT,/REPORT  /g;
    $input=~s/   /  /g;
    @in=split(/  /,$input);

#    @fund=$in[0];
    
    if($i=="0"){
    $final=$in[3].".html";
    open (OUT,">>body.txt") || die "I am not able to write to file";
    open (HEAD,">>head.txt") || die "not able to open temp header";
    print HEAD "<HTML><HEAD><TITLE>Fund Activity Report</TITLE></HEAD>
+<BODY><TABLE border=1><tr><td><strong>Fund Activity Reports:   $in[3]
+</strong></td></tr><TR><td valign='top'><a href='#$fundcode'>$fundcod
+e</a>&nbsp;\n";
    $i=99;
    }
    print HEAD "<a href='#$fundcode'>$fundcode</a>&nbsp;\n";
    print OUT "<strong><a name='$fundcode'>Fund: <u>$in[0]</u> </a>Fun
+dInfo: <u>$in[1] $in[2]</u></strong><br>\n";
    
}
    else {
    print OUT "<pre>$_</pre>\n";
    }


} #### end while stdin
print HEAD "</td></tr></table><br><br>\n"; print OUT "</body></html>\n
+"; close OUT; close HEAD;

#$outfile=~tr/ /_/;
$outfile=~tr/,/_/;
print "$outfile\n";
system "cat head.txt body.txt >>/home/fundlist/test/$final"; system "r
+m head.txt"; system "rm body.txt";

opendir(DIR, "./public_html");
    open (OUT,">/home/fundlist/test/index.html") || die "I am not able
+ to write to file"; print OUT ("<HTML><HEAD><TITLE>Fund List Director
+y</TITLE></HEAD><BODY>\n");
print OUT ("<h4>Directory Listing</h4>\n");

while($file = readdir(DIR) ) {

print OUT ("<A HREF=\"$file\">$file<br>\n");

}
print OUT ("</body></html>\n");
closedir(DIR);
close (OUT);
[download]

Comment on Uninitialized value in concatenation Select or Download Code

Replies are listed 'Best First'.
Re: Uninitialized value in concatenation by moritz (Cardinal) on Jan 25, 2008 at 16:34 UTC
It means that some your variables, for example `$in[3]`, don't contain any values. It also means that some variables don't contain the values that you think they should - so check their values with print statements, the debugger, Data::Dumper or Smart::Comments. And these are not errors (fatal), but warnings (nonfatal).	[reply] [d/l]
Re: Uninitialized value in concatenation by toolic (Bishop) on Jan 25, 2008 at 16:42 UTC
Using `use diagnostics;` in addition to `use warnings;` will give you more information that is sometimes helpful in debugging your problem. It is also a good practice to `use strict;`. Update: something unrelated to consider: you keep opening your `OUT` and `HEAD` filehandles within your first `while` loop, but you do not close them until you are out of the loop.	[reply] [d/l] [select]
Re: Uninitialized value in concatenation by olus (Curate) on Jan 25, 2008 at 16:48 UTC
I copied your script into a new file and validated its syntax `perl -c z3.pl z3.pl syntax OK` [download] But then, I added `use strict;` on line 3 and did the same procedure perl -c z3.pl Global symbol "$i" requires explicit package name at z3.pl line 6. Global symbol "$input" requires explicit package name at z3.pl line 11 +. Global symbol "$input" requires explicit package name at z3.pl line 12 +. Global symbol "$fundcode" requires explicit package name at z3.pl line + 13. Global symbol "$input" requires explicit package name at z3.pl line 13 +. Global symbol "$fundcode" requires explicit package name at z3.pl line + 14. Global symbol "$input" requires explicit package name at z3.pl line 15 +. Global symbol "$input" requires explicit package name at z3.pl line 16 +. Global symbol "$input" requires explicit package name at z3.pl line 18 +. Global symbol "$input" requires explicit package name at z3.pl line 19 +. Global symbol "@in" requires explicit package name at z3.pl line 20. Global symbol "$input" requires explicit package name at z3.pl line 20 +. Global symbol "$i" requires explicit package name at z3.pl line 24. Global symbol "$final" requires explicit package name at z3.pl line 25 +. Global symbol "@in" requires explicit package name at z3.pl line 25. Global symbol "@in" requires explicit package name at z3.pl line 28. Global symbol "$fundcode" requires explicit package name at z3.pl line + 28. Global symbol "$fundcode" requires explicit package name at z3.pl line + 28. Global symbol "$i" requires explicit package name at z3.pl line 29. Global symbol "$fundcode" requires explicit package name at z3.pl line + 31. Global symbol "$fundcode" requires explicit package name at z3.pl line + 31. Global symbol "$fundcode" requires explicit package name at z3.pl line + 32. Global symbol "@in" requires explicit package name at z3.pl line 32. Global symbol "@in" requires explicit package name at z3.pl line 32. Global symbol "@in" requires explicit package name at z3.pl line 32. Global symbol "$outfile" requires explicit package name at z3.pl line +44. Global symbol "$outfile" requires explicit package name at z3.pl line +45. Global symbol "$final" requires explicit package name at z3.pl line 46 +. Global symbol "$file" requires explicit package name at z3.pl line 52. Global symbol "$file" requires explicit package name at z3.pl line 54. Global symbol "$file" requires explicit package name at z3.pl line 54. z3.pl had compilation errors. [download] And that matches line numbers (and a few more) where you are getting those messages. No matter how simple the script may be `use strict` is not to be avoided and can save you some headaches.	[reply] [d/l] [select]
Re: Uninitialized value in concatenation by jwkrahn (Abbot) on Jan 25, 2008 at 18:54 UTC
`$input=~ tr/\"//; $input=~ tr/\'//;` [download] You are replacing the `"` character with itself and the `'` character with itself. If you want to delete characters you have to use the `/d` option: `$input=~ tr/"//d; $input=~ tr/'//d;` [download]	[reply] [d/l] [select]
Re: Uninitialized value in concatenation by FunkyMonk (Bishop) on Jan 25, 2008 at 22:21 UTC
If you can, you might want to install the latest release of Perl, perl 5.10. It will tell you which variable isn't initialised: `$ perl -Mstrict -we 'my $x; print $x' Use of uninitialized value $x in print at -e line 1.` [download] You should be using use strict too.	[reply] [d/l] [select]