R gives you facilities for doing this (using '...' and 'missing') without
passing in a data.frame. For example,
> foo <- function(arg1,arg2,...) { if (missing(arg1)) cat('missing arg1\n');
> print(list(...)) }
> foo(1,2,arg3=3,arg4=4,arg5=5)
$arg3
[1] 3
$arg4
[1] 4
$arg5
[1] 5
> foo(arg2=2,arg3=3,arg4=4,arg5=5)
missing arg1
$arg3
[1] 3
$arg4
[1] 4
$arg5
[1] 5
>
Sent from my iPhone
On May 7, 2013, at 4:29 PM, Keith S Weintraub <kw1...@gmail.com> wrote:
Jim,
Thanks for your comments.
KW
--
On May 6, 2013, at 5:48 PM, Jim Lemon <j...@bitwrit.com.au> wrote:
> see inline
>
> On 05/07/2013 02:14 AM, Keith S Weintraub wrote:
>> Folks,
>>
>> I have been working on an R project that has a few dozen functions.
>>
>> I have some questions that are only tangentially related and might only be a
>> difference in style.
>>
>> 1. Some of my functions take single-row data.frames as input parameters
>> lists. I don't force the user of the function to provide all of the
>> parameters. I use code within a function to test if a particular parameter
>> (column-name) exists in the data.frame and if so use the value of that
>> parameter in a test. If the parameter doesn't exist in the data.frame then
>> some default behavior applies like so:
>>
>> if("rollDown" %in% names(runParams)) rollDown<-runParams[["rollDown"]]
>> else rollDown<-0
>>
>> Is this good style? What are the pitfalls? Is there a better way?
> Whether it is good style or not, you must have been reading my mind. This is
> more or less what I am working on to streamline the increasing number of
> arguments in functions in some of the packages I maintain. At the moment I am
> trying to work out whether it is easier to have one big function to complete
> all the arguments or a set of smaller functions for related groups of
> arguments.
>
>> One nice thing about this method is that if I need to add a new parameter I
>> don't have to change the signature of the function.
>>
>> 2. What is a good way to organize a project with dozens of functions in R?
> Creating a package is an easy and well documented way of
>
> 1) keeping all the functions together
> 2) checking that everything works
> 3) maintaining a record of the evolution of the project
>
> Even a handful of functions can benefit from packaging.
>
>> 3. My project involves a fair amount of simulation. I am not talking hours
>> but some of my "runs" take up to 30 minutes.
>>
>> Suppose I have a "control" function that calls a number of other functions
>> that might benefit from compilation (using the compiler package). Is it
>> better to compile the called functions inside or outside the control
>> function?
>>
>> Is there a good "idiom" or standardized way of turning compilation of the
>> called functions on and off? What about debugging (I use the debug package)?
>>
>> I am perfectly happy with pointers to articles, books and code.
> Jim
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