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Re : st: AW: count with forval and 2 conditions


From   LY Pierrem <lypierrem@yahoo.fr>
To   statalist@hsphsun2.harvard.edu
Subject   Re : st: AW: count with forval and 2 conditions
Date   Fri, 6 Aug 2010 09:36:56 +0000 (GMT)

Dear Martin,

Thank you for your prompt reply. I think you were right. After looking at the document suggested, and several counts by hand to cross check, it seems that the following code produces the desired results. The sort by region and timeposted was indeed what fixed it. (note: the fact that comp2 is initially generated equal to comp1 is obviously irrelevant, it could just be zero or something...)

//maximum possible
sort region timeposted
gen comp2=comp1

//check second condition
//conditional on first being met
forv i =1/`=_N'{
    qui cou if timefunded>=timeposted[`i'] & region == region[`i'] in 1/`i'
    replace comp2=`r(N)'-1 in `i'
}


If anybody finds something wrong with this, please let me know. But I'm now almost sure this works. I'll do a few more hand checks to be even more sure.

Many thanks, Martin! You made my week.

Pierre

--- En date de : Ven 6.8.10, Martin Weiss <martin.weiss1@gmx.de> a écrit :

> De: Martin Weiss <martin.weiss1@gmx.de>
> Objet: st: AW: count with forval and 2 conditions
> À: statalist@hsphsun2.harvard.edu
> Date: Vendredi 6 août 2010, 9h28
> 
> <> 
> 
> 
> So let me guess: You are referring to the thread at http://www.stata.com/statalist/archive/2009-12/msg00578.html
> ? The problem that I can see with your code is that you only
> -sort- on "timeposted". The -if- qualifier "region !=
> region[`i']" also compares on the region even though you
> have not -sort-ed on it. I am not sure whether this is the
> issue spoiling your fun, but it could be. Maybe have a look
> at the judicious deployment of the -bysort- prefix, from
> NJC`s http://www.stata-journal.com/sjpdf.html?articlenum=pr0004
> 
> 
> 
> 
> HTH
> Martin
> 
> 
> -----Ursprüngliche Nachricht-----
> Von: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu]
> Im Auftrag von LY Pierrem
> Gesendet: Freitag, 6. August 2010 09:12
> An: statalist@hsphsun2.harvard.edu
> Betreff: st: count with forval and 2 conditions
> 
> Dear Statalist,
> 
> I have data on funding applicants from different regions
> that look like this
> 
> id       
> timeposted       
> timefunded    comp    region
> 1    Feb 08, 2009 23:00:09   
> Feb 09, 2009 13:23:17    0   
> NAmerica
> 2    Feb 08, 2009 23:30:06   
> Feb 09, 2009 20:50:41    1   
> Asia
> 3    Feb 08, 2009 23:30:06   
> Feb 09, 2009 03:14:32    2   
> Asia
> 4    Feb 09, 2009 00:00:08   
> Feb 09, 2009 01:12:19    3   
> Asia
> 5    Feb 09, 2009 00:10:05   
> Feb 09, 2009 02:48:30    4   
> Asia
> 6    Feb 09, 2009 00:10:05   
> Feb 09, 2009 03:54:15    5   
> Asia
> 7    Feb 09, 2009 01:10:05   
> Feb 09, 2009 15:26:52    6   
> Asia
> 8    Feb 09, 2009 01:10:05   
> Feb 11, 2009 18:35:09    7   
> Asia
> 9    Feb 09, 2009 01:10:05   
> Feb 09, 2009 02:34:56    8   
> Africa
> 10    Feb 09, 2009
> 01:10:05    Feb 09, 2009
> 05:49:01    9    Asia
> 11    Feb 09, 2009
> 01:10:05    Feb 11, 2009
> 00:54:40    10    Asia
> 12    Feb 09, 2009
> 01:20:06    Feb 09, 2009
> 03:56:48    10    Africa
> 13    Feb 09, 2009
> 02:40:13    Feb 09, 2009
> 06:45:58    10    Africa
> 14    Feb 09, 2009
> 02:40:14    Feb 09, 2009
> 03:55:28    11    Africa
> 15    Feb 09, 2009
> 02:40:14    Feb 09, 2009
> 04:36:02    12    Africa
> 16    Feb 09, 2009
> 02:50:05    Feb 09, 2009
> 12:05:11    12    EastEurope
> 17    Feb 09, 2009
> 02:50:05    Feb 09, 2009
> 12:32:17    13    EastEurope
> 18    Feb 09, 2009
> 02:50:05    Feb 09, 2009
> 04:12:15    14    Africa
> 19    Feb 09, 2009
> 03:00:06    Feb 09, 2009
> 05:04:55    15    Africa
> 20    Feb 09, 2009
> 03:00:06    Feb 09, 2009
> 13:15:49    16    EastEurope
> 21    Feb 09, 2009
> 03:30:09    Feb 09, 2009
> 05:19:47    16    Africa
> 
> 
> Timeposted is the time when a person was posted on the
> database of applicants. Timefunded is when she was funded.
> Thanks to earlier help from you, I successfully created a
> new variable, here labeled "comp" which for each person n,
> counts the number of people such that
> 1. they were posted before person n 
> AND 2. were funded after person n was posted.
> 
> In other words, "comp" is the number of people active (i.e.
> posted but not yet funded) on the database at the time each
> person n is posted.
> 
> Now, I am trying to add a condition, in order to count the
> people
> who meet the first condition,
> timefunded<timeposted[`i'], (see below) but ALSO who are
> of the same region. For example, for person id #13, it
> should be 2, i.e. there are 2 other people from Africa who
> were active at the time #13 was posted (versus 10 other
> active people if one ignores the region condition, i.e. my
> "comp" variable above). 
> 
> The new count is called "comp2", using the code 
> 
> //maximum possible
> sort timeposted
> gen comp2=_n-1
> 
> //check second condition
> //conditional on first being met
> forv i =1/`=_N'{
>     qui cou if timefunded<timeposted[`i']
> & region != region[`i'] in 1/`i'
>     replace comp2=comp2-`r(N)' in `i'
> }
> 
> 
> However, this does not do the right calculation.
> (note: to get "comp", the code was exactly the same except
> without the region condition in the qui cou.
> 
> I would be immensely grateful for any suggestions!
> 
> Thanks,
> Pierre
> 
> 
> 
> 
> 
> 
> 
> 
>       
> 
> 
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