CODEWITHSUNDEEP
stata
CompSocialSciR
CompSocialSciR

Reputation: 593

Using a string as variable name

I have a dataset like this:

string_var | var1 | var2 | var3
var2       |  8   |   8  |  4
var3       |  7   |   5  |  7        
var2       |  10  |   10 |  5

I need to test whether var1 is equal to either var2 or var3, depending on the string that is contained in string_var. My problem is to convert these strings into variable names to do something like:

gen test=1 if var1==string_var

where, after the ==, I need some kind of conversion function to let Stata read the string e.g. var2 as the following:

gen test=1 if var1==var2

Upvotes: 2

Views: 867

Answers (1)

Nick Cox
Nick Cox

Reputation: 37208

With just two possibilities, you can branch on the choice. (With several possibilities, I think you'd need a loop.) 

clear 
input str4 string_var  var1  var2  var3
var2         8      8    4
var3         7      5    7        
var2         10     10   5
end 

gen test = cond(string_var == "var2", var1 == var2, var1 == var3) 

list 

     +--------------------------------------+
     | string~r   var1   var2   var3   test |
     |--------------------------------------|
  1. |     var2      8      8      4      1 |
  2. |     var3      7      5      7      1 |
  3. |     var2     10     10      5      1 |
     +--------------------------------------+

EDIT:

Here is a more general solution. (If anyone else thinks of a neater solution, be sure to post.) 

gen test = . 

levelsof string_var, local(names) 

quietly foreach name of local names { 
    replace test = var1 == `name' if string_var == "`name'" 
}

Upvotes: 1

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