I have to agree here. This question (and more generally most of the
questions I've seen you post) do not belong on this particular list.
There are a number of appropriate places where you should be able to get
help with this. Moreover, this question is really trivial, and
shouldn't be a problem once you've been using R for a week or two.
On 7/22/2016 3:13 AM, Martin Maechler wrote:
Randall Pruim <rpr...@calvin.edu>
on Thu, 21 Jul 2016 15:32:00 +0000 writes:
> This isn’t really a teaching question,
Yes, indeed this is NOT about 'teaching R' or
'teaching with R', and hence not appropriate for the
R-SIG-teaching list.
Please, Steven Stoline, stop misusing this list for your questions about R.
There is the R-help mailing list for that, and other fora,
such as Stackoverflow, see
https://www.r-project.org/posting-guide.html and also
https://www.r-project.org/mail.html
Martin Maechler
(ETH Zurich / R Core)
> but for your particular case IIYC, just multiply the squared quantity by
data[,2] before summing. For more general cases, take a look at ifelse().
>> On Jul 21, 2016, at 11:20 AM, Steven Stoline <sstol...@gmail.com> wrote:
>>
>> Dear All: good morning
>>
>> I do need your help how to do the following calculation:
>>
>> Assume we have a matrix 13x2 (say). Two columns named dataval and index
>>
>> dataval index
>> 20 1
>> 11 0
>> 34 0
>> 54 1
>> 76 1
>> 76 0
>> 61 1
>> 88 1
>> 91 0
>> 11 0
>> 23 1
>> 45 1
>> 53 0
>>
>>
data<-matrix(c(20,11,34,54,76,76,61,88,91,11,23,45,53,1,0,0,1,1,0,1,1,0,0,1,1,0),13,2)
>>
>> data
>>
>> I need to perform the calculation:
>>
>> for a = 7 (say)
>>
>> sum((data[ ,1] - a)^2)
>>
>> only for index = data[ ,2] = 1
>>
>>
>> I am expecting the result to be equal to:
>>
>> (20-7)^2 + (54-7)^2+(76-7)^2+(61-7)^2+(88-7)^2+(23-7)^2+(45-7)^2 = 18316
>>
>>
>> Any helps will be highly appreciated.
>>
>>
>> with many thanks
>> steve
>> -------------------------
>> Steven M. Stoline
>> 1123 Forest Avenue
>> Portland, ME 04112
>> sstol...@gmail.com
>>
>> [[alternative HTML version deleted]]
>>
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