Re: rotation of a fixed set

[matthew wickline]

are you looking for a subroutine that does rotations?

     my @ordered = 1..12; # or 1..11 or 'a'..'zz' etc
     my $rot_point = 5; # the index of the value '6'
     my @rotated = rotate( $rot_point, @ordered );

If so, maybe the sub below will do what you need...
 

#!/usr/bin/perl -w
use strict;
my @ordered = 1..12;
for my $rot_num (0..20) {
    print( sprintf('%02d    ', $_),
        "[ ", 
            join( ', ',  &rotate( $rot_num, @ordered )  ),
        " ]\n"
    );
}



sub rotate {
    my $r = shift() % @_; # modulus noop rotations
    @_[   $r .. $#_,   ( $r ? (0..--$r) : () )   ];
    # return end of orig followed by start of orig
}

sub rotate_with_more_input_checking_and_less_fun {
    my $r = shift;
    return @_ unless ($r>0 and @_);
    $r %= @_ if $r >= @_;
    return @_ unless $r > 0;
    my @a = @_;
    push( @a, shift @a) for 1..$r;
    return @a;
}