# Re: [R] Adding elements of matrices of different dimensions

From: Dimitris Rizopoulos <dimitris.rizopoulos_at_med.kuleuven.be>
Date: Tue 27 Jun 2006 - 17:00:30 EST

try the following:

matrix(1:50, ncol = 10) + 1:5
# or
b + drop(a)

I hope it helps.

Best,
Dimitris

Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

```Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://med.kuleuven.be/biostat/
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```
• Original Message ----- From: "michael papenfus" <papenfus@gmail.com> To: <r-help@stat.math.ethz.ch> Sent: Tuesday, June 27, 2006 7:28 AM Subject: [R] Adding elements of matrices of different dimensions

> If I have two matrices:
>
>> a<-matrix(1:5,ncol=1)
>
> [,1]
> [1,] 1
> [2,] 2
> [3,] 3
> [4,] 4
> [5,] 5
>> b<-matrix(1:50,ncol=10)
>
> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
> [1,] 1 6 11 16 21 26 31 36 41 46
> [2,] 2 7 12 17 22 27 32 37 42 47
> [3,] 3 8 13 18 23 28 33 38 43 48
> [4,] 4 9 14 19 24 29 34 39 44 49
> [5,] 5 10 15 20 25 30 35 40 45 50
>
> How can I add a[1,1] to each column in the first row of b.
> and the then add a[2,1] to each column in second row of b
> and so on.
>
> I know there must be a way to use the apply function or nested for
> loops but
> I can't seem to get it working in R.
> thanks,
> michael
>
> [[alternative HTML version deleted]]
>
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