[R] formatting a list

[Tomas Vaisar]

Hi Jim,

I really appreciate your help.
 From the input file I have - 19 columns, 7000 rows - the scan gives me 
the desired format of a list consisting of 19 lists with 7000 values each.
However I need a list of 7000 lists with 19 values each. (e.g. each row 
of my input file should be a separate list bound in a list of all these 
lists)
I use both commands you suggested -
x <- scan('temp.txt', what=c(rep(list(0), 19)))
followed by
x.matrix <- do.call('rbind', x)  # gives 7000 x 19 matrix.

Although this makes a matrix of the correct dimensions it is not the 
"list of lists" the ROCR package expects as input.  Can you convert this 
matrix into a "list of lists"?  Or is there a simple way in R to convert 
a table into such a "list of lists"? 

Thanks again,

Tomas


jim holtman wrote:
> That is what I thought and that is the format that the 'scan' approach
> should provide.  I was just confused when you said that you were going
> to have to transpose it, write it and then read it back in for some
> reason.  I understand that Excel can not handle 7000 columns, but was
> wondering where that came into play.
>
> On 10/21/07, Tomas Vaisar <tvaisar at u.washington.edu> wrote:
>   
>> The data I have is tab delimited file with 7000 lines of 19 values each
>> (representing 7000 permutations on 19 variables). I want to get it into
>> the ROCR package which expects the data to be in lists - single list of
>> 19 values for each permutation, e.g. list of 7000 lists of 19 values each.
>>
>> I hope this is little clearer.
>>
>> Tomas
>>
>> jim holtman wrote:
>>     
>>> What is it that you want to do?  The 'scan' statement give you a list
>>> of length 7000 with 19 entries each.  Do you want to create a matrix
>>> that has 7000 rows by 19 columns?  If so, then you just have to take
>>> the output of the 'scan' and do:
>>>
>>> x.matrix <- do.call('rbind', x)  # gives 7000 x 19 matrix.
>>>
>>> So I am still not sure exactly what your input is and what you want to
>>> do with it.
>>>
>>> On 10/21/07, Tomas Vaisar <tvaisar at u.washington.edu> wrote:
>>>
>>>       
>>>> Hi Jim,
>>>>
>>>> thanks a lot.  It works, however - my other problem is that I need to
>>>> transpose the original table before reading it into the list because the
>>>> data come from Excel and it can't handle 7000 columns.  I could read it
>>>> in R transpose end write into a new tab delim file and then read it back
>>>> in,  but I would think that there might be a way in R to do both.
>>>> Would you know about the way?
>>>>
>>>> Tomas
>>>>
>>>> jim holtman wrote:
>>>>
>>>>         
>>>>> another choice is:
>>>>>
>>>>> x <- scan('temp.txt', what=c(rep(list(0), 19)))
>>>>>
>>>>> On 10/20/07, Tomas Vaisar <tvaisar at u.washington.edu> wrote:
>>>>>
>>>>>
>>>>>           
>>>>>> Hi,
>>>>>>
>>>>>> I am new to R and need to read in a file with 19 columns and 7000 rows
>>>>>> and make it into a list of 7000 lists with 19 items each.  For a
>>>>>> simpler case of 10 by 10 table I used x <-scan("file",
>>>>>> list(0,0,0,0,0,0,0,0,0,0)), perhaps clumsy, but it did the job.
>>>>>> However with the large 19x7000 (which needs to be transposed) I am not
>>>>>> sure how to go about it.
>>>>>>
>>>>>> Coudl somebody suggest a way?
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Tomas
>>>>>>
>>>>>> ______________________________________________
>>>>>> 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.
>>>>>>
>>>>>>
>>>>>>
>>>>>>             
>>>>>           
>>>
>>>       
>
>
>