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From |
Stas Kolenikov <skolenik@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Problem with adding 3 numbers |

Date |
Fri, 16 Oct 2009 23:09:09 -0500 |

Read on -help datatypes- to figure out the relative accuracy of the stored numbers. The default -float- type (which is a terrible default if you ask me) stores numbers with about 4e-8 relative accuracy. Your multiplication by 1e7 produces results accurate to the -state- level only; your localities are well below the round-off error for this type. I have forgotten about these troubles ages ago after putting a line set type double into my profile.do file in Stata directory. On the other hand, a -double- type variable still makes a rather poor identifier, so you might want to -generate- your compound ID variables as -long-: gen long claveloc =((state*10000000)+ (mun2*10000))+loc2 Again, make sure you are still able to store all the numbers accurately, and the largest ID you could ever need does not exceed ~2bln: . di %12.0g c(maxlong) 2147483620 If you have fewer than 214 states, you should be good to go with -long- :)) On Fri, Oct 16, 2009 at 9:27 PM, Kanter, Rebecca <rkanter@jhsph.edu> wrote: > Hi, > > I am trying to add three numbers (1-2 digit code for state plus 3 digit code for municipality + 4 digit code for locality). together unique for each state in a country. I have tried this various ways and each time, after the 1st state, STATA starts to round (I think) some of the numbers. I have tried this numerous ways. No state, municipality, or locality are missing. State is byte. Municipality and locality are strings (that I convert to numeric see below). > > gen munloc=mun+loc > destring munloc, generate(test) > generate ent2=ent*10000000 > generate claveloc=ent2+test > > or whereby: > mun2=real(mun) > loc2=real(loc) > gen claveloc =((state*10000000)+ (mun2*10000))+loc2 > > ****Anyway I try this, I get problems like this: > > state mun loc munloc test state2 claveloc > 2 001 0001 0010001 10001 20000000 20010000 (should be 20010001) > ent mun loc munloc test state2 claveloc > 2 001 0139 0010139 10139 20000000 20010140 (should be 20010139) > > *Should be like this: > > state mun loc munloc test state2 claveloc > 1 001 0001 0010001 10001 10000000 10010001 > > > > Can someone please help me get this to work correctly. > > Thank you so much, > Rebecca > > > ___________________________________________ > Rebecca M. Kanter > PhD Candidate > Johns Hopkins Bloomberg School of Public Health > Department of International Health > Center for Human Nutrition > > * > * 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/ > -- Stas Kolenikov, also found at http://stas.kolenikov.name Small print: I use this email account for mailing lists only. * * 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/

**Follow-Ups**:**RE: st: Problem with adding 3 numbers***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**RE: st: Problem with adding 3 numbers***From:*"Kanter, Rebecca" <rkanter@jhsph.edu>

**References**:**st: Problem with adding 3 numbers***From:*"Kanter, Rebecca" <rkanter@jhsph.edu>

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