Hi johngg! I liked your post. I see what you did with the sprintf. The OP may not understand, so I include a demo for him (you already know this) showing why leading zeroes are necessary to get the "right" numeric result with an alpha sort. I didn't see the need for this, but you bring up a valid point if this matters. 
#!/usr/bin/perl
use warnings;
use strict;

# Simple alpha sort produces wrong numeric order here

my @test = (qw/1 12 10 100 /);
@test = sort @test;
print "@test\n"; #prints "1 10 100 12"

# With leading zero'es, we get "right" numeric answer

@test = (qw/001 012 010 100/);
@test = sort @test;
print "@test\n"; #prints "001 010 012 100"

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I have a small quibble with this line: foreach ( <$inFH> ). With this syntax, I figure that Perl will construct a list of stuff from $inFH and process that list. That will use more memory than a while (<$inFH>){} construct which reads one line at a time from the file handle. No biggie for small files, but this matters for "big" files.

In reply to Re^2: Identifying duplicates in array or hash based on a subset of data by Marshall
in thread Identifying duplicates in array or hash based on a subset of data by Anonymous Monk

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