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Use of uninitialized value problem in Perl script

digioleg54
User

Jun 9, 2017, 8:37 AM

Post #1 of 3 (2402 views)

Use of uninitialized value problem in Perl script	Can't Post

I continue my last post. I have a code:

Code

foreach my $line (@records) { 
	print "We are in the record $line\n"; 
        chop; 
        if (/ TBA/) { 
            my$ln_tp=$_;

It is reading line and print it, however in the error_log I see

Code

Use of uninitialized value $_ in scalar chop at tests1.pl line 47. 
 Use of uninitialized value $_ in pattern match (m//) at tests1.pl line 48.

47 - chop, 48 if

Could you please correct the code, if it is wrong?
This is one of the line

Code

CUSIP|20170504|DMG |100.6340625||1544000 We are in the record CUSIP|20170504|DMG |100.6340625||1544000

The code is not mine, I have to fix it. And I don't understand what is

Code

 if (/ TAB/

. It is trying to compare something with TAB? I don't see, what can be compare like that
Thanks

(This post was edited by digioleg54 on Jun 9, 2017, 9:14 AM)

Laurent_R
Veteran / Moderator

Jun 9, 2017, 11:14 AM

Post #2 of 3 (2393 views)

Re: [digioleg54] Use of uninitialized value problem in Perl script [In reply to]	Can't Post

Hi,

this:

Code

if (/ TBA/) {

is trying to match the / TBA/ regex in the string contained in $_, which would work if you used the $_ topical variable to read your array. For example with code like this:

Code

foreach (@records) {  
	print "We are in the record $_\n";  
        chomp;  
        if (/ TBA/) {  
            my$ln_tp=$_; 
        } 
}

But since you are storing the records in the $line variable, you need to use it for the regex and for the assignment on the next line:

Code

foreach my $line (@records) {  
	print "We are in the record $line\n";  
        chomp $line;  
        if ($line =~ / TBA/) {  
            my$ln_tp = $line; 
        } 
}

Note that I used chomp instead of chop, because this is most probably what you want (remove trailing new line character). chop would remove that last character even if it isn't a new line character, so this is somewhat dangerous when all you want to do is to remove new line characters.

BillKSmith
Veteran

Jun 9, 2017, 2:48 PM

Post #3 of 3 (2389 views)

Re: [digioleg54] Use of uninitialized value problem in Perl script [In reply to]	Can't Post

Quote

The code is not mine, I have to fix it. And I don't understand what is

Code

if (/ TAB/

. It is trying to compare something with TAB? I don't see, what can be compare like that

Refer to the match operator in perlop. (Emphasis mine)

Quote

�m/PATTERN/msixpodualngc
�/PATTERN/msixpodualngc
Searches a string for a pattern match, and in scalar context returns true if it succeeds, false if it fails. If no string is specified via the =~ or !~ operator, the $_ string is searched.

You really should have been able to find this yourself.
Good Luck,
Bill

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