Question : mysql RLIKE '[[:<:]]WA[[:>:]]'

what is the difference between

select * from customers
where address RLIKE 'WA'

and

select * from customers
where address RLIKE '[[:<:]]WA[[:>:]]'

Answer : mysql RLIKE '[[:<:]]WA[[:>:]]'

Map will certainly be faster for the lookup as you would need to loop thru the array to lookup using an array.
For looping thru all elements then an array would be faster but probably not a lot in it (you'd need to do some benchmarking)

Though theres no reason you couldn't maintain an array and a Map, and use the array for looping, and the map for lookups