determine the # of components in a graph

components.r

#!/usr/bin/Rscript

# author: Anton Kratz
# created: Fri Jul 20 11:00:06 PDT 2018

# given a graph in edge list with score field, i.e.:
# FROM_NODE TO_NODE SCORE
# determine the # of components in this graph

suppressPackageStartupMessages(library(igraph))

args = commandArgs(trailingOnly=TRUE)
# test if there is at least one argument: if not, return an error
if (length(args) == 0) {
  stop("specify graph edge list input filename", call.=FALSE)
}

rf <- read.table(args[1], sep="\t")
# mysubset <- rf[which(rf$V3>0.4),]
mysubset <-  rf
akg <- graph_from_data_frame(mysubset, directed = FALSE, vertices = NULL)
coakg <- components(akg)
cat (paste("# of components of ", args[1], ": ", coakg$no, "\n", sep = ""))