[R] Why can't R understand if(num!=NA)?
pdalgd at gmail.com
Fri May 3 19:46:02 CEST 2013
On May 3, 2013, at 17:24 , jpm miao wrote:
> I have a program, when I write
> it yields an error message.
> However, if I write
> it works.
> Why doesn't the first statement work?
Because comparison with an unknown value yields an unknown result.
By the way, comparing a logical value to FALSE is silly:
if ( !is.na(num) ) will do it.
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
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