You could use a hash...

my %h=map{$_++ => $_}('a'..'z'); $h{'z'}='a';
[download]

gives you a hash which looks like this:

a => b
b => c
c => d
d => e
e => f
f => g
g => h
h => i
i => j
j => k
k => l
l => m
m => n
n => o
o => p
p => q
q => r
r => s
s => t
t => u
u => v
v => w
w => x
x => y
y => z
z => a
[download]

andy.