How to avoid printing duplicates

perl_mystery has asked for the wisdom of the Perl Monks concerning the following question:

I want to avoid printing duplicates.I have three variables in a print statement like below.For example if the print statment prints " 1 2 3",this pattern should not be printed.Can someone pls suggest how to do it?

print $line, $match, $link, "\n";
[download]

If the following pattern gets printed,it should not get printed again

1 2 3

Comment on How to avoid printing duplicates Download Code

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Re: How to avoid printing duplicates by Ratazong (Monsignor) on Dec 04, 2010 at 19:52 UTC
When you think duplicate, think hash. untested: `my %patterns; if (!($patterns{"$line, $match, $link"})) # if not yet in the has +h { print $line, $match, $link, "\n"; # print it $patterns{"$line, $match, $link"} = 1; # ... and add it to the + hash }` [download] HTH, Rata	[reply] [d/l]
Re^2: How to avoid printing duplicates by Anonymous Monk on Dec 05, 2010 at 03:07 UTC
I think he meant each variable may be a duplicate of the next, in which case it would be slightly more complex, but that principle (hashes) still does apply.	[reply]
Re: How to avoid printing duplicates by TomDLux (Vicar) on Dec 06, 2010 at 05:14 UTC
You present this over-simplified problem, How do I keep from printing duplicates?, but you say nothing about where the data is coming from. The best solution is to avoid generating duplicates, if you can. As Occam said: Entia non sunt multiplicanda praeter necessitatem.	[reply]