[Rd] minor error in documentation of pmax in base (PR#2513)

Jonathan Baron baron@cattell.psych.upenn.edu
Fri Jan 31 18:58:48 2003

In a way it is not surprising, but some functions that operate on
vectors will coerce their outputs into vectors and others won't.
For example, try

m1 <- array(1:24,c(2,3,4))

It would be nice to say when each of these things will happen.

For example, in the documentaition for ifelse, it says, "returns
a value with the same shape as".  This sort of language would be


On 01/31/03 12:42, Liaw, Andy wrote:
>If I'm not mistaken, matrices and arrays are just vectors with dim
>attribute.  so I'm not surprised that pmax and pmin work as they do.  You
>get the same answer by the following:
>array(pmax(1:24, 24:1), c(2, 3, 4))
>array(pmin(1:24, 24:1), c(2, 3, 4))
>> -----Original Message-----
>> From: baron@cattell.psych.upenn.edu
>> [mailto:baron@cattell.psych.upenn.edu]
>> Sent: Friday, January 31, 2003 12:37 PM
>> To: r-devel@stat.math.ethz.ch
>> Cc: R-bugs@biostat.ku.dk
>> Subject: [Rd] minor error in documentation of pmax in base (PR#2513)
>> The documentation says, "pmax and pmin take several vectors as
>> arguments and return a single vector giving the parallel maxima
>> (or minima) of the vectors."
>> I discovered that, if you use a matrix or array instead of a
>> vector, pmax returns a matrix or array, respectively.
>> This makes pmax and pmin much more useful, and should not be left
>> to people to discover on their own!
>> For example:
>> m1 <- array(1:24,c(2,3,4))
>> m2 <- array(24:1,c(2,3,4))
>> pmax(m1,m2)
>> pmin(m1,m2)
>> Jon Baron
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>> R-devel@stat.math.ethz.ch mailing list
>> http://www.stat.math.ethz.ch/mailman/listinfo/r-devel
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Jonathan Baron, Professor of Psychology, University of Pennsylvania
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