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st: How to capture record info where "something" about the record is true?

From   "Steichen, Thomas J." <[email protected]>
To   <[email protected]>
Subject   st: How to capture record info where "something" about the record is true?
Date   Fri, 22 Jul 2005 14:57:04 -0400

I need to efficiently capture, for example, the record id where something is true about that record.

For example, if I have the following made-up data:

  id x

  a  6
  b  32
  c  6
  d  11

I may want to capture a record id where x = max(x).
I know I can get it via:

  . egen mx = max(x)
  . gen rx = 1 if x == mx
  . sort rx 
  . local id_info = id   (or, more accurately, id[1])
  . di "ID info: `id_info'"
ID info: b

But an egen, gen, and sort seems to be an expensive way to do this with a large dataset.

The above solution will, of course, only capture one record id, where x=max(x).

If I had wanted x=min(x), it would be nice if id_info contained "a c". This is doable also, but becomes even more expensive in
computing time.

Can someone propose a more efficient way or point out a built-in command that I've missed?


Thomas J. Steichen
[email protected]
  Facts do not cease to exist because they are ignored. - Aldous Huxley

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