$t means the 7th item of the array @t. But you
declared my @t=(',',$_); which only has 2 items
( $t and $t ). So when you try $t eq "CA"
then perl says it's uninitialized because that
item does not exist in that list.
The code you posted makes no sense. Try to start
from scratch and organize your thoughts, using
pen and paper if necessary, before and while
writing the code. You're making some progress.
Keep trying, and organize your code:
my $input = "SRC185.xlsx";
my $output = "Output2022.xlsx";
my $workbook = Excel::Writer::XLSX->new( $output );
my $worksheet = $workbook->add_worksheet('List');
my $rowCount = 0;
open(FH, "<", $input ) or die "Can't open $input: $!";
<P> tags added by GrandFather to improve readability
code tags on array elements added by Discipulus