search for: submat

Hi all, I'm trying to learn R after years of Matlab's experience. Here is an issue I couldn't solve today. Consider the following piece of code (written by memory): for(i in 1:n){ submat <- data[1:i,] C <- colSums(submat) } The problem is that at the first iteration, data[1:1,] reduces to a vector and colSums returns an error. This sounds really strange to me because a sum-over-columns operation should have no problem working with columns of length 1. Matlab's &q...

Good morning, I am a new R user and I am trying to learn how to use it. I am trying to solve this problem. I have a dataframe df of daily securities (for a year) earnings as follows: SEC_ID DAY EARNING IT0000001 20070101 5.467 IT0000001 20070102 5.456 IT0000001 20070103 4.954 IT0000001 20070104 3.456 .......................... IT0000002 20070101 1.456 IT0000002 20070102 1.345