[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

From |
Austin Nichols <austinnichols@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: using vector notation to simplify coding |

Date |
Fri, 14 Aug 2009 09:55:07 -0400 |

Dan-- You should reshape the mes variable as well, which then is the measure of calendar month. The j variable after reshape is inconsequential. No merging required, and all subsequent data manipulation becomes easy once you have long-format data. On Fri, Aug 14, 2009 at 9:13 AM, Dan Waldo<dan_waldo@yahoo.com> wrote: > Thanks for the suggestion, Austin. Reshaping is a good idea, although I am not sure how I'd implement that in my particular case: each record has 6 monthly figures (ing_1 through ing_6) but the months they're drawn from (mes_1 through mes_6) are not the same for all records. > > It's helpful to know that each record's months are sequential. So, one semi-hard-code method would be to create a small dataset containing a record for each possible value of mes_1 (in this case, July through October); the record would have mes_1 and def_1 though def_6, the latter being the appropriate months' deflators. Then this file is merged onto the base file: > > . clear > . input mes_1 def_1-def_6 > 1. 7 1.07 1.06 1.05 1.04 1.03 1.02 > 2. 8 1.08 1.07 1.06 1.05 1.04 1.03 > 3. 9 1.09 1.08 1.07 1.06 1.05 1.04 > 4. 10 1.10 1.09 1.08 1.07 1.06 1.05 > 5. end > . save def , replace > . use ingresos , clear > . merge mes_1 using def , sort uniqus > . drop if _merge==2 > . gen ding_1=100*ing_1/def_1 > . gen ding_2=100*ing_2/def_2 > etc > . drop def_1-def_6 > > It's clunky but gets the job done. But it's not generalizable ... and the other solutions offered are. > > Dan > > --- On Wed, 8/12/09, Austin Nichols <austinnichols@gmail.com> wrote: > >> From: Austin Nichols <austinnichols@gmail.com> >> Subject: Re: st: using vector notation to simplify coding >> To: statalist@hsphsun2.harvard.edu >> Date: Wednesday, August 12, 2009, 11:18 AM >> Dan-- >> This is really more a data structure issue--you will save >> yourself a >> lot of trouble in the long run by reorganizing the data, >> for example >> by making it "long" format for panel regressions (help >> reshape). If >> you have month and year on the data, you can -merge- to get >> a cpi >> variable and deflate with a line like: >> g realy=y/cpi >> and see also -cpigen- on SSC. >> >> On Wed, Aug 12, 2009 at 11:12 AM, Kit Baum<baum@bc.edu> >> wrote: >> > <> >> > Dan said >> > >> > Thanks for the clarification, Kit. I am having trouble >> shaking the SAS >> > mindset on this stuff, and your note, along with >> Michael's, have helped a >> > lot. I "get" the mata approach, being a old Fortran >> guy ...it feels like a >> > cumbersome solution in Stata right now, but I am sure >> that is a transitory >> > feeling. >> > >> > Actually it is a very elegant solution, taking >> advantage of the concept of >> > 'view matrices' in Stata. Surely as another old >> Fortran guy you remember the >> > EQUIVALENCE statement. That's what is happening with a >> view matrix (real >> > programmers don't need no steenken pointers!) so that >> changes in Mata to the >> > contents of the matrix (Y in my code) actually changes >> the contents of the >> > Stata variables that populate the matrix. That is very >> powerful (and >> > naturally can be dangerous if misunderstood). >> > >> > See http://ideas.repec.org/p/boc/dsug09/06.html >> > (and ITSP, which illustrates this at greater length) >> > >> > Cheers >> > Kit >> > >> * >> * 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/ > * * 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/

**References**:**Re: st: using vector notation to simplify coding***From:*Dan Waldo <dan_waldo@yahoo.com>

- Prev by Date:
**st: RE: Principal Components Analysis with count data** - Next by Date:
**Re: st: DC09 Stata Conference** - Previous by thread:
**Re: st: using vector notation to simplify coding** - Next by thread:
**st: summation** - Index(es):

© Copyright 1996–2015 StataCorp LP | Terms of use | Privacy | Contact us | What's new | Site index |