Re: [R] matrix math

From: Petr Pikal <petr.pikal_at_precheza.cz>
Date: Thu 05 Jan 2006 - 18:16:52 EST

On 4 Jan 2006 at 14:10, r user wrote:

Date sent:      	Wed, 4 Jan 2006 14:10:24 -0800 (PST)
From:           	r user <ruser2006@yahoo.com>
To:             	rhelp <r-help@stat.math.ethz.ch>
Subject:        	[R] matrix math

> I am using R 2.1.1 in an windows XP environment.
>
> I have 2 dataframes, temp1 and temp2.
>
> Each dataframe has 20 variables (“cocolumns") and 525 observations
> (“rows”). All variables are numeric.
>
> I want to create a new dataframe that also has 20 columns and 525
> rows. The values in this dataframe should be the sum of the 2 other
> dataframe.
>
> (i.e. temp1$column 1+temp2$column1, temp1$column2+temp2$column2,
> etc)
>
> What is the best/easiest way to accomplish this?
>
> Is I wish to "multiply" (instead of sum) the columns, how do I?
>
> I tried:
>
> temp3<-as.matrix(temp1)+as.matrix(temp2)
>
> I get the following error message: “Error in as.matrix(temp1) +
> as.matrix(temp2) :
> non-numeric argument to binary operator”

Hi

although you think all variables are numeric they probably are not.

what does

str(temp1) or str(temp2)

tells you

HTH
Petr

>
>
>
> ---------------------------------
>
> [[alternative HTML version deleted]]
>
>

Petr Pikal
petr.pikal@precheza.cz



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Jan 05 18:24:01 2006

This archive was generated by hypermail 2.1.8 : Thu 05 Jan 2006 - 22:12:49 EST