[R] Multiplication of dataframes

[Dimitris Rizopoulos]

you should first transform them to matrices using data.matrix() and then 
do a matrix multiplication using %*%.

This will create a matrix, which you can then convert to a data frame, 
if you want, using as.data.frame(). For instance, check the following:

d1 <- data.frame(x = rnorm(10), y = rnorm(10))
d2 <- data.frame(x = rnorm(10), y = rnorm(10))

res <- data.matrix(d1) %*% t(data.matrix(d2))
res
as.data.frame(res)


I hope it helps.

Best,
Dimitris


glenn wrote:
> If I have 2 data frames;
> df1:    dim(df1) = (1,10)
> df2:    dim(df2) = (2000,10)
> 
> Both with column header names, how do I multiply them together please. I.e
> create a dateframe dim() = (2000,1)
> 
> Many Thanks in advance
> 
> Glenn
> 
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-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus Medical Center

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