The apply function is the way to iterate over rows or columns of
dataframes or matrices. An example would have made this process easier
testing and I have given up doing that job for
You might try:
apply(observs, 1, function(x) Fn(par, x) )
On Jun 16, 2009, at 11:08 AM, Stu @ AGS wrote:
Hello!
I am trying to write a function with vector and data.frame
parameters that
uses the sum() function and values from the rows of the data.frame.
I need to pass this function as a parameter to optim().
My starting point is:
observs <- data.frame(y, x1, x2, x3)
Fn <- function(par, observs) {
sum( (y - (par[1] * (x1 + 1) * x2^(-par[2]) *
x3^par[3])^2 )
}
y, x1, x2, x3 are all vectors.
I am a bit new to R and I have not been able to find a good
description of
how to iterate over rows in a data.frame.
What is a straightforward way to do this?
What am I missing?
Thanks
Stu
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