Set Choice field based on the reference field

Hello!

I have a very simple requirement, but I am not quite familiar with array concept - for loops, so please help me

I am storing certain values in arrays

property1 = [val1,val2,val3];

property2 = [val4,val5,val6];

property3 = [val7,val8,val9];

In my table, there is a reference field say 'reffield 'and a choice field 'choifield'.

the reference field's display values are generally val1,val2,etc (which are being stored as properties)

so,

If my reffield is one of val1/val2/val3 --> my choifield should be set to choice1

if reffield is one of val4/val5/val6 --> choifield should be set to choice2

if reffield is one of val7/val8/val9 --> choifield should be choice3.

simple if else script is working but there are many values like val1,val2..... It is hard to put all these in if condition. 

How to do this using for loops or any other method?