Re^3: Perl: How to print unmatched data after comparison of two files?

..I only need to print those unmatched data shown as expected result..
use negation not like so:

...
while (<DATA1>) {
    next if /^\s*$/;
    if (/^.+?\s(.+?)\s/) {
        print $_ if not exists $hash{$1}; # note HERE
    }
}
..
[download]

Could you please explain further about hash?
See perlintro

If you tell me, I'll forget.
If you show me, I'll remember.
if you involve me, I'll understand.
--- Author unknown to me

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Re^4: Perl: How to print unmatched data after comparison of two files? by MidLifeXis (Monsignor) on Jul 17, 2013 at 12:33 UTC
(not necessarily to 2teez) Be aware that (see perlop's precedence table) the use of `not` here means that the entire clause on the right side is negated. You can also use `!` to just negate the next closest term. I often give the advice to use (`and`, `or`, `not`) for flow control, and (`&&`, `\|\|`, `!`) for logic. In this case I am not taking the position that this use of `not` is incorrect, just that it is important for the OP to be aware of what it is actually saying. Update: As ambrus stated in the CB: "How about `unless`". --MidLifeXis	[reply] [d/l] [select]
Re^4: Perl: How to print unmatched data after comparison of two files? by WWq (Novice) on Jul 17, 2013 at 09:21 UTC
Thanks a lot 2teez :)	[reply]