[R] Trying to understand a function passed to lapply

Colleagues, I am trying to understand the syntax of a function passed to apply. The code below generates a matrix, and passes the matrix to a function that is called by apply. I don't understand the syntax of the function. In some way the function computes data[,delta]/data[,SE]. I can't

Re: [R] Trying to understand a function passed to lapply

I can't understand how the body of the function, x[c1]/x[c2] refers to the columns data and SE of the matrix data. If you put the line 'str(x)' at the start of myfun(), as in myfun - function(x, c1, c2) { str(x) x[c1]/x[c2] } you would start to see why it works - extracting a

Re: [R] Trying to understand a function passed to lapply

Hi John, What happens is that you have passed two named arguments to your function myfun along with the matrix data. Because these arguments have associated values (delta, SE), these values are substituted into the expression like this: x[delta]/x[SE] which is the return value of myfun. If you