Use of uninitialized value in concatenation (.)

[babcia01]

This is an extract from my code:
my $args1;
my $args2;
my $args3;
:
# the below done in a loop with many lines:
($cpu,$pid,$user,$ni,$time,$args1,$args2,$args3) = split(' ',$line);

$ps_out .= qq['"$args1 $args2 $args3"'];

On execution, I am getting this warning:
Use of uninitialized value in concatenation (.)

The args2 and args3 may often be with no value (spaces).

How do I eliminate the warning?

Thank you

 

[sleipnir214]

Initialize them to a value, even if it is just "" before using them. ______________________________________________________________________
TANSTAAFL!

 

[babcia01]

I did it: in the begining i assigned (my args1 = "", same for arsg2m args3)and also after the ps_out statement to take into consideration that the subsequent line may have space for args2 and args3. Still the same warning.
Thank you again

 

[sleipnir214]

Instead of trying to do it inside the qq, why not do it as a set of if statements? ______________________________________________________________________
TANSTAAFL!

 

[justice41]

Add the following lines after the split statement:

$args2 ||= '';
$args3 ||= '';

If there are not enough fields in the line that you are splitting then $args2 and $args3 will be undefined, no matter what you initialize them to. This is the cause of the warning you get. The above two lines will assign the empty string to the two variables if they are undefined, otherwise it will leave them alone.

jaa

 

[babcia01]

Thank you all. The last one from "jaa" worked as I wanted.