On 19/05/17 21:48, Ramnik Bansal wrote:
Hi,
I need to understand the inconsistent behaviour of & and I operators when
used with NA.
The code below explains this inconsistency
TRUE & NA
[1] NA
FALSE & NA
[1] FALSE
TRUE & NA
[1] NA
FALSE | NA
[1] NA
TRUE | NA
[1] TRUE
TRUE == NA
[1] NA
FALSE == NA
[1] NA
What inconsistency? It all makes complete sense. Think about it.
TRUE & FALSE is FALSE but TRUE & TRUE is TRUE, so TRUE & NA could be
either TRUE or FALSE and consequently is NA.
OTOH FALSE & (anything) is FALSE so FALSE & NA is FALSE.
Und so weiter.
As I said *think* about it; don't just go with your immediate knee-jerk
(simplistic) reaction.
cheers,
Rolf Turner
--
Technical Editor ANZJS
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276
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