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Re: st: Equivalent of Excel's COUNTIF


From   Stas Kolenikov <skolenik@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Equivalent of Excel's COUNTIF
Date   Wed, 16 Nov 2011 11:44:40 -0500

On Wed, Nov 16, 2011 at 11:04 AM, Richard Herron
<richard.c.herron@gmail.com> wrote:
> Here is an alternative solution with -reshape-, -cond-, and -sum-.

Cute solution!

> The last two functions should be fast at any scale, but I don't have
> enough experience with Stata to know if -reshape- is faster than a
> loop.

That's easy to check: set obs 10M instead of 10, and see what will be
faster (and whether the -reshape- will start breaking down with large
data sets; it might or it might not). -reshape- appears to be using a
lot of I/O with explicit -use-, -save- and -merge- in the code; I
thought this would have been written in C or Mata -- there's a
reshape() function in Mata.

-- 
Stas Kolenikov, also found at http://stas.kolenikov.name
Small print: I use this email account for mailing lists only.
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