[R] Equivalent to matlab ".*" operator in R

[Benno Pütz]

It can be simplified a bit, though, as the second operand in the multiplication does not need to be a matrix:

		y * rep(z,each=3)
 
On 19 Nov 2014, at 16:24 , Jeff Newmiller <jdnewmil at dcn.davis.ca.us> wrote:

> When your matrices are the same size, the "*" operator does what you want. The problem is that you have to make a conforming version of z before you can use that operator.
> 
> y*matrix(rep(z,3),ncol=2,byrow=TRUE)
> 
> or
> 
> y*matrix(rep(z,each=3),ncol=2)
> 
> To interpret this, just keep in mind that matrices are folded vectors in R... every matrix can be thought of as a linear vector of columnwise data with dimension attributes.
> 
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> On November 19, 2014 6:43:55 AM PST, "Ruima E." <ruimaximo at gmail.com> wrote:
>> Thank you Chel Hee.
>> 
>> Isn't there a simpler way to do so?
>> 
>> 
>> On Wed, Nov 19, 2014 at 3:35 PM, Chel Hee Lee <chl948 at mail.usask.ca>
>> wrote:
>>>> y = matrix(cbind(c(0, 0.5, 1),c(0, 0.5, 1)),ncol=2)
>>>> z = matrix(c(12, -6),ncol=2)
>>>> t(apply(y, 1, function(x) x*z))
>>>     [,1] [,2]
>>> [1,]    0    0
>>> [2,]    6   -3
>>> [3,]   12   -6
>>> 
>>> I hope this helps.
>>> 
>>> Chel Hee Lee
>>> 
>>> On 14-11-19 08:22 AM, Ruima E. wrote:
>>>> Hi,
>>>> 
>>>> I have this:
>>>> 
>>>> y = matrix(cbind(c(0, 0.5, 1),c(0, 0.5, 1)),ncol=2)
>>>> z = matrix(c(12, -6),ncol=2)
>>>> 
>>>> In matlab I would do this
>>>> 
>>>>> y .* x
>>>> I would get this in matlab
>>>> 
>>>>> ans
>>>> 0    -0
>>>> 6    -3
>>>> 12   -6
>>>> 
>>>> What is the equivalent in R?
>>>> 
>>>> Thanks
>>>> 
>>>>      [[alternative HTML version deleted]]
>>>> 
>>>> ______________________________________________
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>>> 
>> 
>> ______________________________________________
>> 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.
>