st: regexs and regexm

[Simon Falck <sfalckstata@gmail.com>]

Dear Statlist,

Using Stata 11.2, I want to extract a portion of a string variable using 
regular expressions, i.e. -regexs- and -regexm-

This job is a bit tricky because the string variable contains several 
different types of expressions, lengths, and sometimes spaces, with 
information that looks something like this,

string variable
UK/FI/EI
PMSE    NO(20)
PMSE    NO(20),EI(5),GE(35),CN(20)
PMSE2004    NO(50),EI(10),GE(30),UK(30),SW(30)
POLARLIS    FR(220)
LIDAR_GPS    NI(20),NO(20)
IASK    SE(60),NO(20),UK(20)

What I want is to extract (decomposed) information from the string 
variable into new columns, such as,

var1     var2    var3     var4    var5    var6    var7    var8 var9    
var10  var11    var12
UK        FI        EI
PM       SE       NO        20
PM       SE       NO        20        EI        5        GE 30        
UK      30        SE        30

As I understand, one way of doing this is to use Stata´s regular 
expressions: -regexs- and -regexm-, i.e.:

gen x1 = regexs(1)+ regexs(2) if regexm(expnamn, "([a-zA-Z])([a-zA-Z]+)")
gen x2 = regexs(1)+ regexs(2) if regexm(expnamn, "([0-9]+)*([0-9]+)")
..and so on..

However, since the characteristics of the string variable is rich on 
variety this task appears far more complex than what I first thought, 
and I am unable to construct a proper script to decompose the string 
variable in an efficient way.

Any suggestions?

Thanks in advance,
Simon

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