[R] unexpected behaviour with ddply and colwise

[Steve Lianoglou]

Last point ...

On Wed, Apr 7, 2010 at 6:39 PM, Stuart Andrews <stu.andrews at gmail.com> wrote:
>
> Ahhh, I see my error, thanks to Steve and others who mailed me off list.
>
> Perhaps reading a little too quickly, I mis-interpreted the help for ddply,
> in particular, the second argument:
>
>>       ".variables: variables to split data frame by, as quoted variables,
>> a
>>               formula or character vector"
>
> I assumed that I could select entire columns (i.e. the *variables* that
> comprise my data.frame) using this argument.

I'm not sure if this is what you were gunning for, but just in case:

If you wanted your `colwise` function to only run on a certain subset
of columns of the data.frame, you would pass those column names as the
2nd arg to the call to `colwise`.

Check out the examples in ?colwise if that's the case.

-steve

-- 
Steve Lianoglou
Graduate Student: Computational Systems Biology
 | Memorial Sloan-Kettering Cancer Center
 | Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact