R Programming By Example

Using R's way of iterating efficiently

At this point, we're left with a single for loop, which we would like to remove. However, there's a bit of logic in there that gets in the way. This is where the lapply() function comes in handy. As you know from Chapter 1, Introduction to R, this function receives a list of objects that will be sent to a function provided as a second argument, and it will return the results from such function calls in a list. An added benefit of the lapply() function is that it takes care of the memory preallocation for us, which is a very efficient way to reduce execution time in R.

In this case, we encapsulate the logic inside our for loop in a separate function called sma_from_position_1() and use it within our ...