R help - Jun 2006 - Determine the data type of a function to an argument

Hello All:

How can I determing the "types" of args passed to an R function?  For 
example, given the following:


    calculate <- function(...)
    {
        args <- list(...)
        argName     = names(args)

        if (arg1 == character)
            cat("arg1 is a character")
        else
             cat("arg1 is numeric")


        if (arg2 == character)
            cat("arg2 is a character")
        else
            cat("arg2 is a numeric")

    }
    value = calculate(arg1='222' arg2=333)

Programatically, how can I determine if arg1 is a character and arg2 is 
numeric?

Many Thanks:

Alex

Look at ?class and perhaps is?.  i.e.

x=c("1","2","3")
class(x)
[1] "character"

x=c(1,2,3)
class(x)
[1] "numeric"

I hope this helps

Francisco

Dr. Francisco J. Zagmutt
College of Veterinary Medicine and Biomedical Sciences
Colorado State University



>From: "Alex Restrepo" <alex_restrepo at hotmail.com>
>To: r-help at stat.math.ethz.ch
>Subject: [R] Determine the data type of a function to an argument
>Date: Tue, 20 Jun 2006 15:48:03 -0500
>
>Hello All:
>
>How can I determing the "types" of args passed to an R function? 
For
>example, given the following:
>
>
>     calculate <- function(...)
>     {
>         args <- list(...)
>         argName     = names(args)
>
>         if (arg1 == character)
>             cat("arg1 is a character")
>         else
>              cat("arg1 is numeric")
>
>
>         if (arg2 == character)
>             cat("arg2 is a character")
>         else
>             cat("arg2 is a numeric")
>
>     }
>     value = calculate(arg1='222' arg2=333)
>
>Programatically, how can I determine if arg1 is a character and arg2 is
>numeric?
>
>Many Thanks:
>
>Alex
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide! 
>http://www.R-project.org/posting-guide.html