[R] matching matrix columns to a vector

[Dan Davison]

Dan Davison wrote:
> 
> 
> 
> Jagat.K.Sheth wrote:
>> 
>> How about which(colSums(t-v) == 0) ?
>> 
> 
> But what about v=c(2,1,3)? It needs to be something like
> 
> which(colSums((t - v)^2)) == 0
> or
> which(colSums(abs(t - v))) == 0
> 
Sorry, apparently I tried to write a line of R code without using emacs. Bad
idea. I meant
which(colSums((t - v)^2) == 0)
Dan

Dan Davison wrote:
> 
> 
> Dan
> 
> 
> Jagat.K.Sheth wrote:
>> 
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
>> On Behalf Of Salas, Andria Kay
>> Sent: Monday, November 24, 2008 10:04 AM
>> To: r-help at r-project.org
>> Subject: [R] matching matrix columns to a vector
>> 
>> I need help with (hopefully) just one more thing.  I have been fussing
>> with this for quite some time and have decided just to give up and ask!
>> I want to match a column in a matrix to a vector.  I found a "which"
>> command that I thought would be helpful as it does the following:
>> 
>>> g=c(1,5,3,2,7)
>>> which(g==5)
>> [1] 2
>> 
>> As the above gave which placement in the g vector corresponded to 5 (the
>> second place), I need this command to give me which column in a matrix
>> matches to a vector.
>> 
>> This is just a toy example of what I am trying to do:
>>> t=matrix(1:12,3,4)
>>>v=c(1,2,3)
>>>which(t[,j]==v)
>> 
>> This does not work, and with my "real" matrices and vectors, I was
>> getting outputs that did not make sense.  These examples are more to
>> give an idea of what I am aiming to accomplish.
>> 
>> Thank you for all the help!!
>> ______________________________________________
>> 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.
>> 
>> 
> 
> 

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