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st: RE: RE: precision: -insheet- & -outsheet-


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: RE: precision: -insheet- & -outsheet-
Date   Wed, 5 Apr 2006 00:05:17 +0100

disingenuous ! 

Nick 
n.j.cox@durham.ac.uk 

> I am afraid that some of the answer is "Don't do 
> this" (e.g. import from Excel) but no doubt that is not a
> practical answer. 
> 
> Also, the reference to the "actual values" of the variables
> is at best disingenous. Only if the values are integers, and 
> in a few other cases, are such values completely unequivocal. 
> Only just recently Bill Gould explained at considerable length
> how in practice we are usually talking about the best binary 
> approximations. 
> 
> More positively, there is some advice at
> http://www.stata.com/support/faqs/data/newexcel.html
> 
> Although listed as author, I compiled that document in
> self-defence as I was getting questions I couldn't answer 
> from colleagues and students who use Excel. (Except for sets 
> of measure zero, I don't.) Most of the real details came from 
> the people
> also named in the FAQ. 
> 
> Nick 
> n.j.cox@durham.ac.uk 
> 
> clinton.thompson@summitllc.us
> 
> > I am using Stata S/E 9.1 for Macintosh.
> > 
> > This question concerns the issue of retaining data precision, 
> > as it were,
> > when -insheeting- data into Stata from a .csv file and, 
> > conversely, when
> > exporting data from Stata via -outsheet-.
> > 
> > Suppose I have an Excel file that contains large numbers that are
> > presented as scientific notation.  Further suppose that I 
> > save said Excel
> > file as a comma-delimited file (.csv) then import into Stata via
> > -insheet-, along w/ the double option.  After the insheet, an 
> > examination
> > of the data indicates that some degree of precision has been lost --
> > rounding -- even after the variables have been reformatted to 
> > reflect the
> > length & desired format (e.g. %20.2fc).  One clumsy 
> > workaround for this
> > problem involves changing the numeric variable to string via 
> > the insertion
> > of commas into the values, -insheet-ing, then -destring-ing 
> > the variable
> > back into a numeric variable.  As noted, this seems like a terribly
> > cumbersome and clumsy solution -- any suggested alternatives 
> > (e.g. using
> > an alternative to -insheet-)??
> > 
> > On the flip side, i.e. -outsheet-ing the data back into a 
> > .csv file, is it
> > necessary to format any numeric variables into 
> non-scientific notation
> > format so as to retain the actual values of the variables?


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