@a = 'A'..'J'; 
for my $r ( map [ $_, $a[ $_ ] ], 0 .. $#a ) { 
    print "$r->[0]:$r->[1]\n" 
}
0:A
1:B
2:C
3:D
4:E
5:F
6:G
7:H
8:I
9:J