Question

I have a data structure created using read.csv() of dimensions 130, 395. I am trying to iterate over the data by row and return a vector containing a list of lists of the sum over each row in increments of 5 (only from data[,13:395]). I have written the following code, but it returns a vector with sums over intervals of 5 by column and it is also an infinite loop. In other words, I am trying to figure how to make this code finite and work by row.

data <- read.csv(file = "Table.csv")
indexes <- c(13:395)
counter <- 0
a <- c()
list <- c()

for(line in data){
    for(index in indexes){
        while(counter<5){
            a <- c(a, line[index])
            counter = counter + 1
            }
        list <- c(list, sum(a, na.rm = TRUE))
        counter = 0
        a = c()
        }
    }

Thanks for your help

Answer 1

How about this?

library(zoo)
d <- as.data.frame(matrix(1:100,nrow = 4))
> t(apply(d,1,function(x) { rollapply(x,width = 5,FUN = "mean",align = "left") }))
     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13] [,14] [,15] [,16] [,17] [,18] [,19] [,20]
[1,]    9   13   17   21   25   29   33   37   41    45    49    53    57    61    65    69    73    77    81    85
[2,]   10   14   18   22   26   30   34   38   42    46    50    54    58    62    66    70    74    78    82    86
[3,]   11   15   19   23   27   31   35   39   43    47    51    55    59    63    67    71    75    79    83    87
[4,]   12   16   20   24   28   32   36   40   44    48    52    56    60    64    68    72    76    80    84    88
     [,21]
[1,]    89
[2,]    90
[3,]    91
[4,]    92

For your purposes, you’d only pass columns 13:365 (i.e. something like d[,13:365] instead of just d).

I see now that I used mean instead of sum by mistake, but that change is easy to make.