Hi Duncan,
In this case they all had length 1, but I'll be careful at other occasions.
Denis
Le 2011-06-05 à 09:26, Duncan Murdoch a écrit :
> On 11-06-05 8:49 AM, Denis Chabot wrote:
>> Thanks Duncan, I'll go back to if and else!
>
> Be careful, it might not give you the same answer.
>
> I'd use this variation on the advice from ?ifelse:
>
> new.date <- my.date + x
> new.date[is.na(my.date)] <- min(default.date) + x
>
> The thing to watch out for in this construction is that the lengths of the
> vectors come out right. I'm assuming that my.date + x is the same length as
> is.na(my.date)], and that min(default.date) + x is length 1, but I haven't
> tried your code to check.
>
> Duncan Murdoch
>
>>
>> Denis
>> Le 2011-06-05 à 08:39, Duncan Murdoch a écrit :
>>
>>> On 11-06-05 8:23 AM, Denis Chabot wrote:
>>>> Hi,
>>>>
>>>> I was "losing" my dates in a script and upon inspection, found that my
>>>> recent switch from separate "if" and "else" to "ifelse" was the cause. But
>>>> why?
>>>
>>> See ?ifelse. The class of the result is the same as the class of the test,
>>> not the classes of the alternatives. You need to manually attach the class
>>> again, or use a different construction.
>>>
>>> Duncan Murdoch
>>>
>>>>
>>>> my.date = as.POSIXct("2011-06-04 08:00:00")
>>>> default.date = seq(as.POSIXct("2011-01-01 08:00:00"),
>>>> as.POSIXct("2011-09-01 08:00:00"), length=15)
>>>> x = 4 * 60 * 60
>>>> (my.date + x)
>>>> (min(default.date) + x)
>>>> (new.date = ifelse(!is.na(my.date), my.date + x, min(default.date) + x)
>>>> )
>>>>
>>>> (if(!is.na(my.date)) new.date2 = my.date + x else new.date2=
>>>> min(default.date) + x )
>>>>
>>>> On my machine, new.date is "numeric" whereas new.date2 is "POSIXct" and
>>>> "POSIXt", as desired.
>>>>
>>>> sessionInfo()
>>>> R version 2.13.0 (2011-04-13)
>>>> Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
>>>>
>>>> locale:
>>>> [1] fr_CA.UTF-8/fr_CA.UTF-8/C/C/fr_CA.UTF-8/fr_CA.UTF-8
>>>>
>>>> attached base packages:
>>>> [1] stats graphics grDevices utils datasets methods base
>>>>
>>>>
>>>> Thanks in advance,
>>>>
>>>> Denis
>>>> ______________________________________________
>>>> R-help@r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
