I guess lot of ways, but I cna quickly think of two.

1. Create format with code and values, Put the formats in a 
catalog and set option for fmtsearch and apply format to 
teh variable.

2. Create temp dataset with input data in datastep. And use 
proc SQL to join or use DATA step merge.

Table lookup is a process of retriving information from
second dataset and add to first data set. different ways to
do look up.
1. data step with merge function.
2. set statement and Key option.
3. Proc sql into clause, inner join, subquery
4. proc format 5. conditional logics if, where, update
statements. 6. arrays with do loops 7. update statement.