Re: st: stacking unique values of several variables under one new variable

[Maarten Buis <maartenlbuis@gmail.com>]

On Mon, Feb 25, 2013 at 7:15 AM, James Bernard wrote:
> I have a variable ("Technology) that indicates type(s) of a technology
> for each record. I want to aggregate the unique values of this
> variable under one new variable

*---------------- begin example ----------------
// create example data
clear all
input str23 type
"Monoclonals"
"Vaccines"
"Adjuvant, Vaccine"
"Combinchem, Monoclonals"
end

// put each type in a separate variable
split type, p(", ")

// original variable is no longer needed
drop type

// reshape such that the types are stacked
gen id = _n
reshape long type, i(id) j(order)

// id and order are no longer needed
drop id order

// remove missing values
drop if type == ""

// remove duplicates
bys type : keep if _n == 1

// see the results
list
*----------------- end example -----------------
(For more on examples I sent to the Statalist see:
 http://www.maartenbuis.nl/example_faq )

Hope this helps,
Maarten

---------------------------------
Maarten L. Buis
WZB
Reichpietschufer 50
10785 Berlin
Germany

http://www.maartenbuis.nl
---------------------------------
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