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From |
"NEYMOTIN, FLORENCE" <neymotin@calmail.berkeley.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: RE: question on datatypes |

Date |
Thu, 20 Oct 2005 05:40:42 -0700 |

that is a good idea. thanks for the help!! florence On Thu, 20 Oct 2005 10:25:08 +0100 "Nick Cox" <n.j.cox@durham.ac.uk> wrote:

This is a frequent question on Statalist.

If you what are reading in, although it looks

like a standard numeric variable with a decimal

point, is really some kind of identifier or code, then I think by far the safest strategy is to read it in as a string variable and then do string manipulations on it. This can include removing the point.

Even if you read it in as -float- and then convert

to -long- it is all too likely that errors will

be introduced in the last digit or so.

As a thread yesterday advised, -search precision-

and look at the FAQs there mentioned. The underlying

issue is that computers are really doing calculations

in binary, not decimal. A massive amount of cleverness goes into

hiding this fact from the user, and even the programmer, but it is inescapable and on occasions can bite you.

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

NEYMOTIN, FLORENCE

I have variables that are coded in as 2-3 digits and 6 decimal places after that, e.g. 150.089873 and I want to convert this to get rid of the decimal places so it looks like 150089873 but when I just multiply by 1000000 then it keeps storing it as a "float" display i.e. 1.5E8 and more than that, the last decimal places are actually INCORRECT in the new version...it will say 1.50089875 instead...which is INCORRECT. I am using Stata 8 and that is where this problem occurs. I was wondering what the easiest way is to change datatypes that something is input in so that it will not be a problem.

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**References**:**st: RE: question on datatypes***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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