search for: cumapply

Is there anything like cumsum and cumprod but which allows you to apply an arbitrary function instead of sum and product? In other words, I want a function cumfunc(x, f) that returns a vector, so that for all n up to the length of x cumapply(x,f)[n] = f(x[1:n]) This would give cumsum and cumprod as special cases when f=sum or f=prod. I could write such a function, but I can't see a way to do it without a loop, so I'm wondering if such a function exists that may be speedier. Thanks, -- --OKB (not okblacke) Brendan Ba...