[R] find the "next non-NA" value within each row of a data-frame

#I wish to find the "next non-NA" value within each row of a data-frame. #e.g. I have a data frame mydata. Rows 1, 2 & 3 have soem NA values. mydata <- data.frame(matrix(seq(20*6), 20, 6)) mydata[1,3:5] <-  NA mydata[2,2:3] <-  NA mydata[2,5] <-  NA mydata[3,6] <-  NA mydata[1:3,] #this loop acco

[R] "moving product", by rows, of a dataframe?

What is a "good" way to calculate the "moving product", for each row of a dataframe, where I wish to be able to specify the length of the moving product? Depending on my needs, I'd like to be able to specify the "length" over which to calculate the moving average (in this example, length=3). Fo