matrix math

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matrix math

R user-3
  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”


               
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Re: matrix math

PIKAL Petr


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

Date sent:       Wed, 4 Jan 2006 14:10:24 -0800 (PST)
From:           r user <[hidden email]>
To:             rhelp <[hidden email]>
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





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Petr Pikal
[hidden email]

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