[R] passing dataframe col name through cbind()

[Eric Rupley]

Thanks!  Makes sense now.


On Nov 8, 2011, at 1:32 PM, jim holtman wrote:

> Try this:
> 
>> cbind(scores[,1,drop = FALSE], scores[,2:3])
>  name round1 round2
> 1  Bob     40      5
> 2  Ron     30      6
> 3  Bud     20      4
>> 
> 
> Then do ?'[' to learn about 'drop'
> 
> On Tue, Nov 8, 2011 at 1:06 PM, Eric Rupley <erupley at umich.edu> wrote:
>> 
>> 
>> 
>> Hi all ---
>> 
>> I note that the column name of the first column in a dataframe does not necessarily get passed on when using cbind (example below)…
>> 
>> I'm looking for help in clarifying why this behavior occurs, and how I can get all col names, including the first, passed on to the result…while I suspect it's obvious and documented to the cognoscenti, it's puzzling me…
>> 
>> Many thanks for any help on this...
>> Eric
>> 
>>> scores <- data.frame(name=c("Bob","Ron","Bud"),round1=c(40,30,20),round2=c(5,6,4)) #some toy data
>>> 
>>> scores
>>  name round1 round2
>> 1  Bob     40      5
>> 2  Ron     30      6
>> 3  Bud     20      4
>>> 
>> 
>>> cbind(scores[,1],total=rowSums(scores[,2:3]),scores[,2:3])
>>  scores[, 1] total round1 round2
>> 1         Bob    45     40      5
>> 2         Ron    36     30      6
>> 3         Bud    24     20      4
>>> 
>> 
>> ...first column renamed...
>> 
>> …yet this passes all column names:
>> 
>>> cbind(scores[,1:3])
>>  name round1 round2
>> 1  Bob     40      5
>> 2  Ron     30      6
>> 3  Bud     20      4
>>> 
>> 
>> …but this doesn't:
>> 
>>> cbind(scores[,1],scores[,2:3])
>>  scores[, 1] round1 round2
>> 1         Bob     40      5
>> 2         Ron     30      6
>> 3         Bud     20      4
>> 
>> 
>> --
>>  Eric Rupley
>>  University of Michigan, Museum of Anthropology
>>  1109 Geddes Ave, Rm. 4013
>>  Ann Arbor, MI 48109-1079
>> 
>>  erupley at umich.edu
>>  +1.734.276.8572
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>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>> 
> 
> 
> 
> -- 
> Jim Holtman
> Data Munger Guru
> 
> What is the problem that you are trying to solve?
> Tell me what you want to do, not how you want to do it.
> 
>