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

Jeff Newmiller jdnewmil at dcn.davis.CA.us
Wed Nov 19 16:24:48 CET 2014

```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]]
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
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>>
>
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