data-raw/internet_routers.R

In rrrlw/ICON: Provides Easy Access to Complex Systems Datasets

# open file connection
fin <- file("data-raw/internet_routers.gml", "r")

# skip lines with node labeling (don't care about labels for this dataset)
#   is there more efficient way to skip lines??
invisible(readLines(fin, n = 114819))

# read 6 lines at a time, edge-by-edge
LINES_PER_EDGE <- 5
TOTAL_EDGES <- 48436
internet_routers <- data.frame(Node1 = character(TOTAL_EDGES),
                               Node2 = character(TOTAL_EDGES),
                               stringsAsFactors = FALSE)
counter <- 1
while (TRUE) {
  # read and check if EOF
  lines <- readLines(fin, n = LINES_PER_EDGE)
  if (length(lines) < LINES_PER_EDGE) break

  # isolate elements of each line in block
  splitter <- strsplit(lines, split = " ",
                       fixed = TRUE)

  # get last elements of lines 3, 4, 5 in block of 6
  node_1 <- splitter[[3]][length(splitter[[3]])]
  node_2 <- splitter[[4]][length(splitter[[4]])]

  # save in edge list format
  internet_routers$Node1[counter] <- node_1
  internet_routers$Node2[counter] <- node_2

  # update counter
  counter <- counter + 1
}

# close file connection
close(fin)

# save data as rda
#usethis::use_data(internet_routers, overwrite = TRUE)
save(internet_routers, file = "data-host/internet_routers.rda")