[R] looking for alternative of 'if-else'

[Duncan Murdoch]

On 06/07/2008 11:58 AM, Arun Kumar Saha wrote:
> I am not sure whether I could understand all things. Here is my code :
> 
> library(zoo)
> # an reproducible example
> SD <- 1
> date1 <- seq(as.Date("2001-01-01"), as.Date("2002-12-1"), by = "day")
> len1 <- length(date1)
> set.seed(1) # to make it reproducible
> data1 <- zoo(rnorm(len1), date1)
> plot(data1)
> 
> # calculation for monthly or quarterly mean
> calc = function(frequ = c("M S", "Q S"))
>               {
>                switch(frequ
>                        "M S" = aggregate(data1, as.yearmon, mean)
>                        "Q S" = aggregate(data1, as.yearqtr, mean))
>               }

switch() is a function, so you need commas between its arguments, i.e.

switch(frequ,
                         "M S" = aggregate(data1, as.yearmon, mean),
                         "Q S" = aggregate(data1, as.yearqtr, mean))

With that change I see no errors.

Duncan Murdoch


> However I am getting lot of errors while executing. Any further suggestion?
> 
> Regards,
> 
> 
> 
> On Sun, Jul 6, 2008 at 3:38 PM, <ctu at bigred.unl.edu> wrote:
> 
>> Why don't you try "switch" Let me assume that you want to calculate a=3 and
>> b =5 by using one of "MEAN", "SUM","MIN", and "MAX functions. Then you could
>> write your code: (If you want to calculate "MEAN")
>>
>>  example<-function(fun=c("MEAN", "SUM", "MIN", "MAX")){
>> +   fun<-match.arg(fun);a=3;b=5
>> +   switch(  fun,
>> +            MEAN=(a+b)/2,
>> +            SUM=a+b,
>> +            MIN=min(a,b),
>> +            MAX=max(a,b))
>> +            }
>>
>>>            example("MEAN")
>>>
>> [1] 4
>>
>>>  Hope this is helpful,
>> Chunhao Tu
>>
>>
>>
>>
>>
>>
>> Quoting Arun Kumar Saha <arun.kumar.saha at gmail.com>:
>>
>>  There is "if-else" loop if I have to choose 1 item from a 2-item list.
>>> However if I have a list of 4 items (let say) then how i can choose a
>>> single
>>> item without employing 'if-else' loop? I mean in VBA I can use
>>> "select-case", is there any equivalent in R as well?
>>>
>>> Regards,
>>>
>>>        [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help at 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.
>>>
>>>
>>
>>
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at 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.