Hi, everyone I am new to grasshopper, but i like it already!

What i want to do is match a List of Letters to specific numbers.

Lets say i have

A

D

E

G

A

D

I want to get 

1

4

6

7

1

4

Is like saying A=1, D=4, E=6, G=7. The series of Letters is Long but the different letters are only 10 I don't know if that makes any difference.

Thanks!