>>>>> "[EMAIL PROTECTED]" == [EMAIL PROTECTED] fr <[EMAIL PROTECTED]>
>>>>> on Tue, 12 Dec 2006 22:24:33 +0100 writes:
[EMAIL PROTECTED]> ...ifelse, a function of three **vector**
[EMAIL PROTECTED]> arguments.... Yes !! I misunderstood the
[EMAIL PROTECTED]> functioning of ifelse.
Seems to happen more an more often.
When I teach "R programming" I nowadays usually emphasize that people
should often *NOT* use ifelse().
In other words, I think ifelse() is much over-used in situations
where something else would be both clearer and more efficient.
Is there a document / book around which lures people into
misusing ifelse() so frequently?
Martin Maechler, ETH Zurich
[EMAIL PROTECTED]> Peter Dalgaard wrote:
>> [EMAIL PROTECTED] wrote:
>>> What is puzzling me is that rnorm(1) is only evaluated
>>> *twice*, one time for each branch, with only 2 different
>>> random deviates, instead of giving ten different random
>>> deviates. y1 has indeed 10 values but with only 2
>>> different ones.
>>>
>> I find it more puzzling why you expect that ifelse, a
>> function of three vector arguments, would cause its input
>> arguments to be reevaluated for every element of the
>> result.
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