Statalist The Stata Listserver


[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

RE: st: Looping across variables in variable columns


From   "Mungai, Edward" <[email protected]>
To   <[email protected]>, <[email protected]>
Subject   RE: st: Looping across variables in variable columns
Date   Fri, 27 Apr 2007 10:35:49 +0200

Sorry this should have been egen -rowtotal-. No mystery. 
 
I still would have liked to figure out how to pass variables to -rowtotal- which would have made my task easier. 
 
Below is part of what I tried given that variables -age- and - year- are known.  Sorry it may be too basic stata for most people and I prefer readable long code!.
 
generate yr16 = year - age + 16

generate yr18 = yr16 + 2

tostring startyr, generate(yr16)

tostring stopyr, generate(yr18)

generate startpos = "sehead" + startyr if (yr16>=1968)

generate stoppos = "sehead" + stopyr  if (yr18<=2005)

generate timespan = "("+startpos + " - " + stoppos+")"

egen prsemp = rowtotal(sehead1968 sehead1969 sehead1970)

 

Edward 


________________________________

From: [email protected] on behalf of Nick Cox
Sent: Fri 4/27/2007 10:09 AM
To: [email protected]
Subject: RE: st: Looping across variables in variable columns



Glad you were helped by the responses.

Meanwhile, the mystery of what -rowcount- is remains.

Nick
[email protected]

Mungai, Edward

> Thank you all who gave ideas on this querry.
> 
> Being new to stata I have chosen and  managed to implement
> solution 1B and taken into consideration other comments
> relating to missing values. I am motivated to learn more stata!.
 
n j cox

> I can't find -rowcount- using -findit- or Google. Recall the
> precept in
> the Statalist FAQ:
>
> "Say what command(s) you are using. If they are not part of official
> Stata, say where they come from: the STB/SJ, SSC, or other archives."
>
> That said, this is a nice problem. It has got enough spin (cricket
> sense, not public relations!) to be interesting, yet yields
> to a little knowledge of Stata.

...

Mungai, Edward <[email protected]>

> I have seen discussions on looping across an unknown number of columns
> which can be solved by -reshape-.
>
> My question is how to sum across columns where the number of columns
> varies from one observation to the next.  i.e. I may need to
> sum columns
> 2 to 5 for the first observation but from columns 4 to  11 for the
> second observation. In all cases the summation is done across a set of
> adjacent columns.
>
> I have tried to use -rowcount-,  and the looping functions
> but as far as
> I can tell all sum across a fixed number of columns from one
> observation
> to the next. But there is something good also; the information on the
> column to  begin and the column to end the summation for each
> observation is contained  in two adjacent column which are
> the same for
> all the observations.

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/




This message has been scanned for viruses by TRENDMICRO,
an IESE technology affiliate company  and global leader in antivirus and content security software.

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2024 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index