[R] loop over matrix: subscript out of bounds

[Rui Barradas]

Hello,

Eric is right but...

You have two assignments. The second sets a value that will be 
overwritten is the next iteration by myMatrix[i,i] = -1 when 'i' becomes 
the next value.

If you fix the second index and use 'j', you might as well do

myMatrix[] = -1
myMatrix[, ncol(myMatrix)] = 1

Hope this helps,

Rui Barradas

Às 10:24 de 06/08/2018, Eric Berger escreveu:
> Both loops are on 'i', which is a bad idea. :-)
> Also myMatrix[i,i+1] will be out-of-bounds if i = ncol(myMatrix)
> 
> 
> On Mon, Aug 6, 2018 at 12:02 PM, Maija Sirkjärvi <maija.sirkjarvi using gmail.com>
> wrote:
> 
>> I have a basic for loop with a simple matrix. The code is doing what it is
>> supposed to do, but I'm still wondering the error "subscript out of
>> bounds". What would be a smoother way to code such a basic for loop?
>>
>> myMatrix <- matrix(0,5,12)
>> for(i in 1:nrow(myMatrix)) {
>>    for(i in 1:ncol(myMatrix)) {
>>      myMatrix[i,i] = -1
>>      myMatrix[i,i+1] = 1
>> }}
>> print(myMatrix)
>>
>> Thanks in advance!
>>
>>          [[alternative HTML version deleted]]
>>
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> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>