Rename the array variable @data to @lines for the sake of clarity.

Alternatively, don't slurp the entire file into an array in the first place. Simply process the file line by line, which is easily done in Perl.

If you process the file line by line, then you'll need to delay printing every line until after you've read the next line and made whatever changes you need to make to the previous line:

my $previous_line;

LINE:
while (my $line = <>) {
    next LINE if $line =~ m/disregard this line/;

    chomp $line;

    # Here's where you implement your algorithm
    # to compare the value on line $line with the
    # value on line $previous_line and print the
    # appropriate ouput line

    $previous_line = $line;
}

# Here's where you print the last line
# modified as appropriate given that
# there is no next line

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You asked for concepts, I gave you concepts.

In reply to Re: Append Next Line To Current Line by Jim
in thread Append Next Line To Current Line by Anonymous Monk

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