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From |
Ronan Conroy <rconroy@rcsi.ie> |

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

Subject |
Re: st: Stata cannot do math? |

Date |
Thu, 19 May 2011 11:25:03 +0100 |

On 2011 Beal 19, at 01:20, Conor Hughes wrote: > Hi, > Stata can certainly do math, just not quite the same math you're used > to. This is an issue of floating point arithmetic. For example, > replace > count a == 100.1 > in your code with > count a == float(100.1) I have a basic puzzle, which has just occurred to me: Stata cannot find any observations that satisfy the condition count if a == 100.1 we know that Stata is representing the contents of the variable a as an inexact binary representation of 100.1, but why does it not represent the right hand argument in exactly the same way, causing the two to be equal? How does Stata represent the quantity 100.1 when it evaluates the expression a == 100.1? Curious… Ronán Conroy rconroy@rcsi.ie Associate Professor Division of Population Health Sciences Royal College of Surgeons in Ireland Beaux Lane House Dublin 2 * * 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: Stata cannot do math?***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: Stata cannot do math?***From:*Maarten Buis <maartenlbuis@gmail.com>

**References**:**st: Stata cannot do math?***From:*Yu Xue <snowrain@gmail.com>

**Re: st: Stata cannot do math?***From:*Conor Hughes <cbhughes@uchicago.edu>

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