[R] Why can't R understand if(num!=NA)?
dwinsemius at comcast.net
Sat May 4 18:28:07 CEST 2013
On May 3, 2013, at 10:58 PM, peter dalgaard wrote:
> On May 3, 2013, at 21:36 , David Winsemius wrote:
>> On May 3, 2013, at 10:46 AM, peter dalgaard wrote:
>>> Because comparison with an unknown value yields an unknown result.
>> Anything else would violate the Second Law of Thermodynamics. We cannot have comparisons reducing entropy, now can we? Uncertainty cannot run uphill.
> Now what does this say about SAS, where the missing value is smaller than all regular numbers? I.e.,
> iteen = (age < 20);
> turns people of unknown age into instant teenagers.
And are handled as zero when included in calculations using SUM ( as, I also read, does SPSS).
So SAS comparisons are still increasing entropy. Quantum mechanics says there is no real vacuum state, so maybe that's where those not-really-missing missing values are ending up after they confound our notions of existence.
Alameda, CA, USA
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