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”
>
>
>
> ---------------------------------

> $16.99/mo. or less

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Re: matrix math

Jack Tanner
>  I have 2 dataframes, temp1 and temp2.
>
>  Each dataframe has 20 variables (&#147;cocolumns") and 525 observations
>(&#147;rows&#148;).  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.

>foo <- data.frame(c(1,1,1,1),c(2,2,2,2))
>bar <- data.frame(c(1,2,3,4),c(5,6,7,8))
>foo+bar
  c.1..1..1..1. c.2..2..2..2.
1             2             7
2             3             8
3             4             9
4             5            10

If your data frames are actually data frames, it should work.
>class(foo)
[1] "data.frame"

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