st: how to implement a dictionary (aka map, look-up table)

[Andrin Foster <akf7@case.edu>]

I'm trying to set a value based on observation variables matching
relevant dictionary entries.
I've tried to implement a dictionary amongst the variables in Stata,
however, I can't compare my results to the dictionary because the
dictionary entries and results are counted as different observations.

my code was:
gen Value = MetaValue if X==MetaX & Y==MetaY & Z==MetaZ

where the data used was formatted as such:

==================================================
X        Y        Z        MetaX        MetaY        MetaZ        MetaValue
--------------------------------------------------------------------------------------
1        5        3          .                  .                  .
                .
3        2        7          .                  .                  .
                .
9        1        4          .                  .                  .
                .
.         .         .           1                 1                 1
                2
.         .         .           1                 1                 2
                3
.         .         .           1                 2                 1
                5
==================================================

Running the above code will not output an error code but will instead
produce all missing values since the comparisons always resolve to
false.

In psudocode, Stata is currently running...
for i in range observations:
        Value[i] = MetaValue[i] if X[i]==MetaX[i] & Y[i]==MetaY[i] &
Z[i]==MetaZ[i]

...when what I need is...
for i in range observations:
    for k in range dictionary:
            Value[i] = MetaValue[k] if X[i]==MetaX[k] & Y[i]==MetaY[k]
& Z[i]==MetaZ[k]


What is the proper function or data format to achieve my goal?

I'm using Stata 12 on Mac OS 10.7.5

-- 
Andrin Knight Foster
Case Western '12
Economics, English
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