[R] Matrix: Problem with the code

[markleeds at verizon.net]

Charlotte: I ran your code because I wasn't clear on it and your way 
would cause more matrices than the person requested. So
I think the code below it, although not too short, does what the person 
asked. Thanks though because I understand outer better now.

temp <- matrix(c(1,2,3,4,5,6),ncol=2)
print(temp)

#One of those more elegant ways:
print(temp)
outer(temp,1:p,'^')One of those more elegant ways:


# THIS WAY I THINK GIVES WHAT THEY WANT

sapply(1:ncol(temp), function(.col) {
   temp[,.col]^.col
})



On Fri, Jan 9, 2009 at  7:40 PM, Charlotte Wickham wrote:

> One of those more elegant ways:
> outer(x, 1:p, "^")
>
> Charlotte
>
> On Fri, Jan 9, 2009 at 4:24 PM, Sarah Goslee <sarah.goslee at gmail.com> 
> wrote:
>> Well, mat doesn't have any dimensions / isn't a matrix, and we don't
>> know what p is supposed to be. But leaving aside those little 
>> details,
>> do you perhaps want something like this:
>>
>>      x<-c(23,67,2,87,9,63,8,2,35,6,91,41,22,3)
>>      p <- 5
>>      mat<- matrix(0, nrow=p, ncol=length(x))
>>      for(j in 1:length(x))
>>      {
>>          for(i in 1:p)
>>              mat[i,j]<-x[j]^i
>>      }
>>
>> Two notes: I didn't try it out, and if that's what you want rather
>> than a toy example
>> of a larger problem, there are more elegant ways to do it in R.
>>
>> Sarah
>>
>> On Fri, Jan 9, 2009 at 6:42 PM, Bhargab Chattopadhyay
>> <bhargab_1 at yahoo.com> wrote:
>>> Hi,
>>>
>>>
>>> Can any one please explain why the following code doesn't work? Or 
>>> can anyone suggest an alternative.
>>> Suppose
>>>       x<-c(23,67,2,87,9,63,8,2,35,6,91,41,22,3)
>>>        mat<-0;
>>>        for(j in 1:length(x))
>>>        {
>>>           for(i in 1:p)
>>>                mat[i,j]<-x[j]^i;
>>>        }
>>>    Actually I want to have a matrix with p columns such that each 
>>> column will have the elements of  x^(column#).
>>>
>>> Thanks in advance.
>>>
>>> Bhargab
>>>
>>>
>>>
>>
>>
>>
>> --
>> Sarah Goslee
>> http://www.functionaldiversity.org
>>
>> ______________________________________________
>> 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.
>>
>
> ______________________________________________
> 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.