$hash = {
k1 => [a1, b1, c1, d1],
k2 => [a2, b2, c2, d1],
k3 => [a3, b3, c3, d3]
k4 => [a4, b4, c4, d3]
}
For the arrays where the d's are equal i want to do a numerical comparision on the a's and add a priority number at the end

The output i expect
$hash = {
k1 => [a1, b1, c1, d1, 1],
k2 => [a2, b2, c2, d1, 2],
k3 => [a3, b3, c3, d3, 2]
k4 => [a4, b4, c4, d3, 1]
}