[R] Data.Frame Multiplication
zeileis at ci.tuwien.ac.at
Thu Apr 18 13:14:00 CEST 2002
Christian Schulz wrote:
> Have got any R-proffessional a starting point for me
> how i can write me a function which multiply every column with
> every other column in the data.frame - indenpendent from the dim's .
You could start from a function that multiplies a chosen column `col' of
a data.frame `df' with the following columns
multiply <- function(df, col) df[,col] * df[,-(1:col), drop = FALSE]
and then apply that to your data.frame `mydata' like
sapply(1:(ncol(mydata) - 1), function(x) multiply(mydata, x))
For the latter part, there might be a better way to do that depending on
how you want to format the output...
> Thanks in advance
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