{Diverted to R-devel}
>>>>> "BDR" == Prof Brian Ripley <[EMAIL PROTECTED]>
>>>>> on Tue, 6 Jun 2006 21:14:01 +0100 (BST) writes:
BDR> On Tue, 6 Jun 2006, [EMAIL PROTECTED]
BDR> wrote:
>> Hi ,
>>
>> When I sort a vector of POSIXct values in R-2.3.0 and
>> R-2.3.1, I get a vector of numeric values and this gets
>> some of my code to crash (class object creation). Is that
>> a R bug?
BDR> No, it is as documented: see ?sort
BDR> As from R 2.3.0, all attributes are removed from
BDR> the return value except names, which are sorted. (If
BDR> 'partial' is specified even the names are removed.)
BDR> Note, the class is an attribute. For many classes
BDR> sorting destroys the appropriateness of the class.
Indeed, and I agree this a good change.
However, the above also suggests that ideally, sort() would be
a generic function.
One good reason for sort() not being generic now is the fact
that method dispatch costs a bit, *and* that we like sort() to
be really fast.
One way to achieve a generic sort() and keep the possibility of
of very fast sort() --- similarly to rep() and rep.int()
would be to rename the current sort into something like
sortNum() {"Num" for numeric}, make sort() into a generic,
and replace sort() by sortNum() in those code parts which need
to remain optimally fast.
>> In the mean time. I'll try to override the sort function
>> for the POSIXct objects.
BDR> You can restore the class if appropriate.
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
