Thanks for many prompt and useful comments. The question was: if x is
the vector
> x <- c( 2, NA, 1, 5, 3)
> x
[1] 2 NA 1 5 3
Then x == 5 yields
> x == 5
[1] FALSE NA FALSE TRUE FALSE
whereas what I want is
FALSE FALSE FALSE TRUE FALSE
#--------------
Matthew Dowle sent a simple solution:
> x
[1] 2 NA 1 5 3> x==5 & !is.na(x)
[1] FALSE FALSE FALSE TRUE FALSE
Thanks also to Brian Ripley who suggested that I look at chapter 2 of
MASS4, and Eric Lecoutre who pointed out that the 'which' function could
be useful for this problem.
John Miyamoto
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John Miyamoto, Dept. of Psychology, Box 351525
University of Washington, Seattle, WA 98195-1525
Phone 206-543-0805, Fax 206-685-3157, Email jmiyamot at u.washington.edu
Homepage http://faculty.washington.edu/jmiyamot/
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