[R] Stumped with subsetting

Sundar Dorai-Raj sundar.dorai-raj at PDF.COM
Thu Jul 29 21:46:18 CEST 2004



Sundar Dorai-Raj wrote:

> 
> 
> Peter Wilkinson wrote:
> 
>> This seems like such a trivial thing to do:
>>
>> given a data.frame DF and variables w,v, x,y,z I can do
>>
>> DF["x"] or DF[c("x","y")]
>>
>> if I create a vector, mylist = c("x",y")
>>
>> then I do DF[mylist]
>>
>> I am not getting x and y, I get something else.
>>
>>
>> what is the correct way to subset a data.frame by columns using a 
>> vector, as if I were doing DF["x","y"]?
>>
>> Peter
>>
>> ______________________________________________
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>> PLEASE do read the posting guide! 
>> http://www.R-project.org/posting-guide.html
> 
> 
> You want DF[, mylist]. DF[mylist] returns a list. You may want to look 
> at "An Introduction to R", which covers this topic.
> 

Sorry, typed too quickly.

DF[mylist] and DF[, mylist] are the same if mylist is a vector with more 
than one element.

After re-reading your post, I'm not quite sure what you are expecting. 
Sorry for any confusion....

--sundar




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