[R] character substitution within a variable name

[Duncan Murdoch]

On 11-11-23 3:23 PM, matric wrote:
> Thanks Duncan,
> I knew it. But if I use the complete variable name, I'll have far too
> many arguments for my function....

Maybe a new design is in order.

Duncan Murdoch

>
> On 23 November 2011 20:59, Duncan Murdoch-2 [via R]
> <ml-node+s789695n4101308h84 at n4.nabble.com>  wrote:
>> On 23/11/2011 2:29 PM, matric wrote:
>>> Hi,
>>> I'd like to create a function that accepts as arguments a string that is
>>> to
>>> be substituted within a variable name. For instance, suppose I have a data
>>> frame df:
>>>
>>> df<-data.frame(x_narrow=c(rnorm(100,0,1)),x_wide=c(rnorm(100,0,10)))
>>>
>>> What I have in mind is something like:
>>>
>>> f<- function(string){
>>> var = paste("x_",string,sep = "")
>>> df$var
>>> }
>>>
>>> which does not work. Any suggestion for modifications? Thanks in advance,
>> For indexing a dataframe, use the name as the column index:
>>
>> df[, var]
>>
>> will work.
>>
>> Duncan Murdoch
>>
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