[R] table() reading problem

[Jim Lemon]

On 03/16/2011 08:20 PM, fre wrote:
> I have the following problem:
>
> I have some string with numbers like k. I want to have a table like the
> function table() gives. However I am not able to call the first row, the 1,
> 2, 3, 5, 6 or 9. I tried to do that by a data.frame, but that doesn't seem
> to work either. The levels keep bothering me.
>
> This is an example of the code:
>
> k<-c(1,1,1,1,1,3,5,6,2,1,3,9,2,3,1,1,1)
>> table(k)
> k
> 1 2 3 5 6 9
> 9 2 3 1 1 1
>> x<-table(k)
>>
>> dim(x)
> [1] 6
>>
>> x[1] #But i only want the one
> 1
> 9
>>
>> x<-data.frame(x)
>>
>> x[1,1] #You are not allowed to use this one for example 3*x[1,1] is
>> impossible
> [1] 1
> Levels: 1 2 3 5 6 9
>>
>
> I hope anyone has an idea of using the table function without this
> inconvenience. I thought about writing a counter myself, but that seems
> complicated.
> Because I have to examine very large examples later on, I don't want to slow
> the calculations down if possible.
>
> Thanks for your help in advance.
>
Hi Frederique,
It seems to me that you want the names of the table rather than the 
counts, as Sarah has already suggested. So:

as.numeric(names(x))

should give you what you want. However, if all you want to do is 
determine the unique elements of k, then:

unique(k)

might be what you are seeking.

Jim