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From |
"Sergiy Radyakin" <serjradyakin@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Teach an old dog new tricks |

Date |
Thu, 8 May 2008 12:28:52 -0400 |

Thank you Austin. But your code will call summarize NxM times, where N and M are the numbers of categories within each variable specified in by() and each time summarize will look through the whole dataset. And this is where the efficiency is lost. I believe there is only one loop through the dataset necessary in this case, regardles of N and M. I just hope you've had the code already and didn't devise it specifically for my query. Thank you, Sergiy Radyakin On 5/8/08, Austin Nichols <austinnichols@gmail.com> wrote: > Sergiy Radyakin <serjradyakin@gmail.com>: > Easier in Mata, perhaps, but still easy to put in an ado: > _______________________________________ > prog tabmat > version 8.2 > syntax varname [fw aw iw], by(varlist min=1 max=2) Matname(string) [replace] > cap conf matrix `matname' > if _rc!=111 & "`replace'"=="" { > di as err "Matrix `matname' already defined;" _n "specify" _c > di as txt " replace " as err "option to overwrite" > error 110 > } > cap matrix drop `matname' > tokenize `by' > tempvar iv jv > tempname v > egen long `iv'=group(`1') > su `iv', meanonly > loc maxi=r(max) > egen long `jv'=group(`2') > su `jv', meanonly > loc maxj=r(max) > forv j=1/`maxj' { > su `2' if `jv'==`j', meanonly > loc col: label (`2') `=r(mean)' > loc colc: subinstr local col "." "`=char(183)'", all > loc colnam `"`colnam' "`colc'""' > } > forv i=1/`maxi' { > su `1' if `iv'==`i', meanonly > loc row: label (`1') `=r(mean)' > loc rowc: subinstr local row "." "`=char(183)'", all > loc rownam `"`rownam' "`rowc'""' > forv j=1/`maxj' { > su `varlist' [`weight'`exp'] if `iv'==`i' & `jv'==`j', meanonly > if r(N)>0 loc m=r(mean) > else loc m=. > mat `v'=nullmat(`v') , `m' > } > mat `matname'=nullmat(`matname') \ `v' > mat drop `v' > } > matrix rownames `matname' = `rownam' > matrix colnames `matname' = `colnam' > matrix roweq `matname' = `1': > matrix coleq `matname' = `2': > mat li `matname' > end > _______________________________________ > sysuse auto, clear > table rep78 head, c(mean price) > tabmat price, by(rep78 head) mat(A) > > On Thu, May 8, 2008 at 10:16 AM, Sergiy Radyakin <serjradyakin@gmail.com> wrote: > > Hello Statalisters, > > > > I am looking for a way to get the matrix of means, which is displayed > > but not saved by, e.g.: > > > > sysuse auto > > table rep78 head, c(mean price) > > > > The (relatively new) svy commands allow this, but they are quite slow > > for the purpose. -table- was in Stata for ages, but it still does not > > save any matrix results. > > > > I am aware of an option replace, which saves the means in the dataset, > > but it destroys the data, - something I am trying to avoid. Adding > > preserve/restore will slow the program down sufficiently enough to > > reject this way of doing it. > > > > Is it possible to obtain a matrix of means from table (or another > > command with a similar functionality) (preferred) ? Or is it possible > > to tell table,replace to keep the existing data and add the computed > > statistics as new variables (good)? > > > > Note that tabstat does not allow what I am looking, since it only > > supports one var in the by() clause, and I will need to call it N > > times (where N is the number of categories in the second var) and > > combine the columns together, which is not fast either. > > > > Also note, that while > > > > tabulate rep78 foreign, matcell(A) > > > > is a valid syntax, > > > > tabulate rep78 foreign, matcell(A) summarize(price) mean > > > > which presumably could be the solution I am looking for, is not valid: > > r(198); option matcell() not allowed > > > > Any suggestions are welcomed. > > > > Thank you, > > Sergiy Radyakin > > * > > * 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/ > > > * > * 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/ > * * 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/

**Follow-Ups**:**Re: st: Teach an old dog new tricks***From:*"Austin Nichols" <austinnichols@gmail.com>

**References**:**st: Teach an old dog new tricks***From:*"Sergiy Radyakin" <serjradyakin@gmail.com>

**Re: st: Teach an old dog new tricks***From:*"Austin Nichols" <austinnichols@gmail.com>

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