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From |
Zhangqunzi <zhangqunzi@googlemail.com> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: Calculate product from two dta files |

Date |
Wed, 7 Nov 2012 19:10:59 +0100 |

Thanks a lot for ur kind advice, Nick. 在 Nov 7, 2012，11:23 AM，Nick Cox <njcoxstata@gmail.com> 写道： > You asked this yesterday and no-one wanted to wrap their head around it. > > As I understand it you seek here not just one product price * share > but several, so if each file is already too big for comfort, what > structure precisely are you seeking? > > There are some small things you can do: > > 1. Your dates are being held as values like 19700701. If that's a > string or a large integer, convert to Stata daily dates, so that for > example 19700701 if stored as a string or long could be stored as an > int instead, a storage saving of 75% for that variable. > > 2. -compress- anyway. It will do no harm. > > There is really one solution here (other than Stata grinding exceedingly slow): > > It seems to me that you need more memory. I am guessing that this is > the start of a project and you are doing early basic manipulations. > You've not even started on the serious statistical analysis. You are > going to be hitting this problem again and again. You need to talk to > your boss(es)/supervisor/advisor. > > It's still true that you have an inadvisable data structure. I have > asserted this twice before. If you had a long data structure, then the > product price*share would just be one multiplication. That wouldn't > solve your memory problem, however. > > Nick > > > On Wed, Nov 7, 2012 at 9:31 AM, Zhangqunzi <zhangqunzi@googlemail.com> wrote: > >>> I have two dta files having the same structure : >>> >>> Dta1 >>> time firm price 1 2 3 4 >>> 19700701. 0.1. 12. 14. 3 >>> Dta2 >>> Time firm share 1 2 3 4 >>> 19700701. 10 20. 30. 40 >>> >>> I want to get the product of price*share then generate a new dat file to store the result. >>> >>> The varlists from dta1,2 are not the same, eg p1 p3 p5. S1 S3 S5. Also the numbers are not continuous numbers. >>> >>> Also my cimputer's memory is not enough only 730mb, the two dtas are 600mb, if u calculate the product in one dta file it will exceed the memory limit. > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/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/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**References**:**st: Calculate product from two dta files***From:*Zhangqunzi <zhangqunzi@googlemail.com>

**st: Calculate product from two dta files***From:*Zhangqunzi <zhangqunzi@googlemail.com>

**Re: st: Calculate product from two dta files***From:*Nick Cox <njcoxstata@gmail.com>

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