[R] How can I improve an ugly, dumb hack

[Bert Gunter]

On Thu, Sep 6, 2012 at 10:20 AM, David Winsemius <dwinsemius at comcast.net> wrote:
<snipped>

> I guess this means you are not the one performing the d$c <- m step? If you were under control of that step, you can get different (and more to your liking)  behavior with 'cbind.data.frame':

Correct. d is given to me already, as described. I constructed it in
my post only to provide an example of what it might look like. I
apologize for evidently being unclear about this (and I tried real
hard ... sigh....).

-- Bert


>
>> cbind(d, m)
>   a b x y
> 1 1 4 a d
> 2 2 5 b e
> 3 3 6 c f
>> ncol( cbind(d, m) )
> [1] 4
>
>
>>
>> Now what I wish to do is programmatically convert d to a 4 column
>> frame with names c("a","b","x","y"). Of course:
>>
>> 1. The column classes/modes must be preserved (character going to
>> factor and numeric remaining numeric).
>>
>> 2. I assume that I do not know a priori which of d's
>> components/columns are matrices and which are vectors.
>>
>> 3. There may be many more columns which are vectors or matrix than
>> just the three in this little example.
>>
>> I can easily and sensibly accomplish these 3 tasks, but the problem is
>> that I run afoul of data frame column naming procedures in doing so,
>> about which the data.frame Help page says rather enigmatically:
>>
>> "How the names of the data frame are created is complex, and the rest
>> of this paragraph is only the basic story." Indeed!
>> (This, of course, is shorthand for "Go look at the source if you want
>> to know!" )
>>
>> Anyway, AFAICT from the Help, any "simple" approach to conversion
>> using data.frame results in "c.x" and "c.y" for the names of the last
>> two columns. I **can** get what I want by explicitly constructing the
>> vector of names via the following ugly hack; my question is, can it be
>> improved?
>>
>>> dd <- do.call(data.frame,d)
>>
>>> dd
>>  a b c.x c.y
>> 1 1 4   a   d
>> 2 2 5   b   e
>> 3 3 6   c   f
>>
>>> ncol(dd)
>> [1] 4
>>
>>> cnames <- sapply(d,colnames)
>>> cnames
>> $a
>> NULL
>>
>> $b
>> NULL
>>
>> $c
>> [1] "x" "y"
>>
>>
>>> names(dd) <-  unlist(ifelse(sapply(cnames,is.null),names(d),cnames))
>>  ##Yuck!
>>
>>> dd
>>  a b x y
>> 1 1 4 a d
>> 2 2 5 b e
>> 3 3 6 c f
>>
>> Cheers to all,
>> Bert
>>
>>
>> --
>>
>> Bert Gunter
>> Genentech Nonclinical Biostatistics
>>
>> Internal Contact Info:
>> Phone: 467-7374
>> Website:
>> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
>>
>> ______________________________________________
>> 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.
>
> David Winsemius, MD
> Alameda, CA, USA
>



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm