Elegant way of creating categorical variable from set of disjoint dummy variables?

[Nils Enevoldsen]

Is there a clever way to simplify this procedure?

g regionstr = ""
foreach region in _MENA _SSAF _LAC _WEOFF _EECA _SEAS {
    replace regionstr = "`region'" if `region'
}
encode regionstr, g(region)

We may assume that the set of dummy variables is disjoint. I have no preference about which dummy gets which value (e.g. _MENA = 3), but the values should be labeled. This seems like a common thing to want to do, but I don't see a more elegant way to do it.

[Nick Cox]

Another way to do it. You know how to encode

* absit sandbox; hic est sandbox 
 
clear 

set obs 6 

tokenize "_MENA _SSAF _LAC _WEOFF _EECA _SEAS" 

forval j = 1/6 { 
     gen ``j'' = _n == `j' 
} 


list, sep(0)  

     +-----------------------------------------------+
     | _MENA   _SSAF   _LAC   _WEOFF   _EECA   _SEAS |
     |-----------------------------------------------|
  1. |     1       0      0        0       0       0 |
  2. |     0       1      0        0       0       0 |
  3. |     0       0      1        0       0       0 |
  4. |     0       0      0        1       0       0 |
  5. |     0       0      0        0       1       0 |
  6. |     0       0      0        0       0       1 |
     +-----------------------------------------------+

. 
* you start here 
tokenize "_MENA _SSAF _LAC _WEOFF _EECA _SEAS" 

gen regionstr = "" 
. 
quietly forval j = 1/6 { 
    local J : subinstr local `j' "_" "", all
    replace regionstr = "`J'" if ``j'' 
} 

 
list, sep(0) 

     +----------------------------------------------------------+
     | _MENA   _SSAF   _LAC   _WEOFF   _EECA   _SEAS   region~r |
     |----------------------------------------------------------|
  1. |     1       0      0        0       0       0       MENA |
  2. |     0       1      0        0       0       0       SSAF |
  3. |     0       0      1        0       0       0        LAC |
  4. |     0       0      0        1       0       0      WEOFF |
  5. |     0       0      0        0       1       0       EECA |
  6. |     0       0      0        0       0       1       SEAS |
     +----------------------------------------------------------+