Re: Difference between two arrays

[injunjoel]

Greetings,
I liked the hash approach holli suggested.
Here are my thoughts.

#!/usr/bin/perl -w
use strict;

my $before = [qw(1 2 3 4 5 6 7 8 9 10)];
my $after  = [qw(2 3 4 5 1 6 7 8 9 10)];

my %start;
@start{@{$before}} = @{$after};

#every little shift.
my %moved = map{
    ($_ != $start{$_}) ? ($_, $start{$_}) : ()
    }keys %start;

#shifts larger than one.
my %huge_offset = map{
    (abs($_ - $start{$_}) > 1) ? ($_, $start{$_}) : ()
    } keys %start;

#lets check what we have...
print "BEFORE:\t";
print "@$before\n";

print "AFTER:\t";
print "@$after\n";

print "\nOFFSETS:\n";
print "$moved{$_}: ".($start{$_}-1)." to ".($_ - 1)."\n" for( sort {$a
+<=>$b} keys %moved);

print "\nHUGE OFFSETS:\n";
print "$huge_offset{$_}: ".($start{$_}-1)." to ".($_ - 1)."\n" for( so
+rt {$a<=>$b} keys %huge_offset);

and the output.

BEFORE:  1 2 3 4 5 6 7 8 9 10
AFTER:   2 3 4 5 1 6 7 8 9 10

OFFSETS:
2: 1 to 0
3: 2 to 1
4: 3 to 2
5: 4 to 3
1: 0 to 4

HUGE OFFSETS:
1: 0 to 4

-InjunJoel