I have a CSV file I am manipulating into something that is readable by my other program. Perl has been a big help so far. There is a significant learning curve when it comes to dereferencing arrays and their contents. That is probably part of my problem.

I would like to initialize a new field in my CSV to receive extracted data when I parse an existing field. If there was always a result from the parse then I wouldn't have an "Use of uninitialized value in substitution" message later on.

How do I set a dereferenced array to ""?

Am I asking the right Question?

Right now the following doesn't work.

#Initialize to first character of first field, no warnings
#Creates extra unneeded data.
($row->[15]) = $row->[0] =~ /(.)/;

#This appears to match undefined and sets it to "", warnings
#^ * matches null string many times in regex; marked by <--HERE in m/ 
+(^ * <-- HERE $) / at convertACsv.pl line 86.
#Use of uninitialized value in substitution (s///) at convertACsv.pl l
+ine 86, <_GEN_0> line 1.
$row->[15] =~ s/ (^ *$) //gx;

#This appears to match undefined and sets it to "", warnings
#Use of uninitialized value in substitution (s///) at convertACsv.pl l
+ine 86, <_GEN_0> line 1.
$row->[15] =~ s/ (^z) //gx;
#oops, dropped the "\"
$row->[15] =~ s/ (^\z) //gx;

#Why doesn't one of these work?
($row->[15]) = "";
($row->[15]) = ("");

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In reply to Initialize or Match undef without warning by JobC

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