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Antwort: st: numbering observations


From   "Hans J. Baumgartner" <hbaumgartner@diw.de>
To   statalist@hsphsun2.harvard.edu
Subject   Antwort: st: numbering observations
Date   Fri, 15 Apr 2005 18:34:38 +0200

I am not sure what you attempt to do but I'd generate the count variable 
by the following lines:


1) make sure that date is formated into a "Stata-date" check [U]27. 
2) 
sort dw date
by dw: gen count=_n if dw=="friday"

I hope this helps anyway
Hans 





++++++++++++++++++++++++++++++++
Hans J. Baumgartner
Dept. Public Economics
DIW Berlin
German Institut for Economic Research
phone: +49/30/89789-307
fax :      +49/30/89789-114
URL: www.diw.de
          www.hansbaumgartner.de
++++++++++++++++++++++++++++++++

owner-statalist@hsphsun2.harvard.edu wrote on 15/04/2005 14:37:54:

> I have data of the form:
> 
> date      dw      incid
> 6/may/00   friday      5
> 7/may/00   saturday   9
> 13/may/00   friday      10
> 14/may/00   saturday   12
> 
> dw is day of week and incid is the number of violent incidents recorded 
> in police stats.
> 
> I wanted to collapse by weekend (here assuming a weekend is a Friday and 

> Saturday) and therefore added in the following id (count):
> 
> gen count = 0
> 
> local cntr = 1
> forval i = 1(2)`=_N' {
> qui replace count = `cntr' in `i'
> local cntr = `cntr' + 1
> }
> local cntr = 1
> forval i = 2(2)`=_N' {
> qui replace count = `cntr' in `i'
> local cntr = `cntr' + 1
> }
> 
> which gives:
> 
> date      dw      incid   count
> 6/may/00   friday      5   1
> 7/may/00   saturday   9   1
> 13/may/00   friday      10   2
> 14/may/00   saturday   12   2
> 
> and then:
> 
> collapse (sum) incid (min) date, by(count)
> 
> I have two questions.  First, I am certain I have seen a more elegant 
> way of creating the count id posted on Statalist but searching has not 
> revealed anything.  Is there one?
> 
> More importantly, if, for some reason, there is a missing saturday in 
> the data (there isn't at the moment but it is a growing dataset) the 
> collapse ..., by(count) will not work.  Is there an easier way of 
> numbering successive weekends in Stata?
> 
> Regards
> 
> Simon Moore
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> 

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