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Anything in official -egen- that expects to be fed a -varlist- does not allow -by-. Intuitively: You select the _columns_ that you want these functions to process. Functions that expect anything other than a -varlist- do sometimes allow the -by- prefix: You select chunks of _rows_ that should be treated as units for the purposes of the calculation...
HTH
Martin
-----Ursprüngliche Nachricht-----
Von: [email protected] [mailto:[email protected]] Im Auftrag von Ekaterina Hertog
Gesendet: Sonntag, 25. Oktober 2009 20:07
An: [email protected]
Betreff: Re: st: addition of variables in Stata 11
Dear Nick, Martin and John,
Thank you very much for the advice! Nick's and Martin's clarifications
on the impossibility of using the -by option is taken.
Sincerely yours,
Ekaterina
Nick Cox wrote:
> Please note:
>
> 1. This is the same function as -egen, rowtotal()- named in my earlier post. -rsum()- was renamed -rowtotal()- in Stata 9.
>
> 2. However, -by()- is irrelevant to row-wise operations and is in any case not supported (i.e. illegal) with this function.
>
> Nick
> [email protected]
>
> John Ataguba
>
> I suppose these are variables created in rows. You can try:
>
> egen newvar = rsum(citotal*)
>
> Note that you can also combine this with the by option if you want to restrict to a certain group or so...
>
> Ekaterina Hertog <[email protected]>
>
> I have a set of variables which denote population by age group in a
> location a given individual lives in my dataset and I want to add them
> up to total population in a location where each individual lives.
> The names of the variables I have look as follows:
> citotal1519 (meaning total population of 15 to 19 year olds in the city)
> citotal2024 (meaning total population of 20 to 24 year olds in the city)
> citotal2529 (meaning total population of 25 to 29 year olds in the city)
> …
> citotal7074 (meaning total population of 70 to 74 year olds in the city)
>
> I was wondering if it might be possible to somehow ask Stata to add all
> the variables which start with citotal?
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
--
Ekaterina Hertog (née Korobtseva)
Career Development Fellow
Department of Sociology and Nissan Institute of Japanese Studies
University of Oxford
27 Winchester Road
Oxford
OX2 6NA
United Kingdom
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
