Here's a 62 char solution, imploying half a schwatzian transform:

sub g{
#234567890123456789012345678901234567890123456789012345678901234567890
my$c=pop;(sort{@$a[1]<=>@$b[1]}map{[$_,abs($_-$c)]}@_)[0]->[0]
}
[download]

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Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain