st: RE: AW: Decimal Precision with Destring

["Sutton, Bennett W." <BSutton@imf.org>]

Martin,

Owing to the greater expertise of you and Nick, I have repeated two suggestions from you and found that in fact Stata is specifying the precision to 15 decimals, but now have a better understanding of my problem:

* note pcpie is str19
.destring pcpie, gen(test1) force
.format test1 %20.0g
.gen double test2 = real(pcpie)
.format test2 %20.0g

Indeed I am getting the precision to 15 decimal places.

.list year pcpie test1 test2 if year >= 2007 & year <= 2008 & ifscode == 313

      | year                 pcpie                test1                test2 |
      |----------------------------------------------------------------------|
1161. | 2007   116.477290339629000   116.47729033962899   116.47729033962899 |
1162. | 2008   121.777007050082000   121.77700705008201   121.77700705008201 |

However note that test1 and test2 have decimal precision that does not exist in the string variable (pcpie).  On account of this when I calculate a percent change of the of test1 and test2 I am getting results that round up to 4.6 instead of down to 4.5 in year 2008. 


.gen pch1 = (test1/L1.test1-1)*100
.format pch1 %20.0g
.gen pch2 = (test2/L1.test2-1)*100
.format pch2 %20.0g
.list year pcpie pch1 pch2 if year >= 2007 & year <= 2008 & ifscode == 313

      | year                 pcpie                 pch1                 pch2 |
      |----------------------------------------------------------------------|
1161. | 2007   116.477290339629000   2.8499999046325684   2.8499999046325684 |
1162. | 2008   121.777007050082000   4.5500001907348633   4.5500001907348633 |


Note: taking the growth rate of numbers in pcpie you get a number that rounds down to 4.5.

I know these are insanely small hairs to be splitting, but unfortunately this work is going into a publication and I need to make sure that the rounded result will be 4.5 and not 4.6.  (not just here but in many, many other calculations.)

Many thanks for your suggestions,

Ben

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Martin Weiss
Sent: Monday, April 19, 2010 11:14 AM
To: statalist@hsphsun2.harvard.edu
Subject: st: AW: RE: AW: AW: Decimal Precision with Destring


<> 

"Neither option you've sent are working for me."



What does "not working" mean? Note the FAQ...



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Sutton, Bennett
W.
Gesendet: Montag, 19. April 2010 16:47
An: statalist@hsphsun2.harvard.edu
Betreff: st: RE: AW: AW: Decimal Precision with Destring

Many thanks for your suggestions.

Neither option you've sent are working for me.

I'm using stata SE 10.  Is there a setting somewhere which may be
controlling the default decimal precision?


Ben



-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Martin Weiss
Sent: Monday, April 19, 2010 10:42 AM
To: statalist@hsphsun2.harvard.edu
Subject: st: AW: AW: Decimal Precision with Destring


<> 

-destring- seems to work as well:


*************
clear*

inp str17 myvar
2.343541098765432
2.398784389359001
3.219439049039405
3.199038538208222
end

destring myvar, gen(mynewvar)
format mynewvar %18.0g
l, noo
*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Martin Weiss
Gesendet: Montag, 19. April 2010 16:31
An: statalist@hsphsun2.harvard.edu
Betreff: st: AW: Decimal Precision with Destring


<> 

This code does seem to work, using your second approach:

*************
clear*

inp str17 myvar
2.343541098765432
2.398784389359001
3.219439049039405
3.199038538208222
end

list, noo

gen double mynewvar=real(myvar)
format mynewvar %18.0g
l, noo
*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Sutton, Bennett
W.
Gesendet: Montag, 19. April 2010 16:25
An: statalist@hsphsun2.harvard.edu
Betreff: st: Decimal Precision with Destring

Hello all,

I found one post on this from 5 years ago.  But no resolution to the issue
was posted.  Wondering if anyone has since encountered and surmounted this
problem:

I am insheet-ing a .csv file with decimal precision set at 15 places in
excel.  But after insheeting into stata, the series are data type double,
but only have precision to 10 places.  I'm working with hyperinflation
countries and the lack of precision is producing some incorrect results in
calculations.

I have also tried reading the data in as string variables which at least
preserves the 15 digit precision, but destring-ing the data results in loss
of precision again to 10 decimal places.

Any known work arounds?

Many thanks!

Ben

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