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Re^3: What does 'next if $hash{$elem}++;' mean?

by inman (Curate)
on Feb 17, 2006 at 15:51 UTC ( #530980=note: print w/ replies, xml ) Need Help??


in reply to Re^2: What does 'next if $hash{$elem}++;' mean?
in thread What does 'next if $hash{$elem}++;' mean?

It isn't necessary to do all of the intermediate processing. You can read a line and check it all at the same time.

The line is used as a hash key. The value is tested before being incremented and the line is added to the array.

my %seen; while (<PROCESSED_FILE>){ push @unique, $_ unless $seen{$_}++; }

This is OK if the hash doesn't grow to big. Using MD5 hashes of lines is an uesful technique.


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