How to pass command-line arguments when calling source() on an R file within another R file

Question

In one R file, I plan to source another R file that supports reading two command-line arguments. This sounds like a trivial task but I couldn\'t find a solution online. Any

Answer 1

An extended version of @Matthew Plourde's answer. What I usually do is to have an if statement to check if the command line arguments have been defined, and read them otherwise.

In addition I try to use the argparse library to read command line arguments, as it provides a tidier syntax and better documentation.

file to be sourced

 if (!exists("args")) {
         suppressPackageStartupMessages(library("argparse"))
         parser <- ArgumentParser()
         parser$add_argument("-a", "--arg1", type="character", defalt="a",
               help="First parameter [default %(defult)s]")
         parser$add_argument("-b", "--arg2", type="character", defalt="b",
               help="Second parameter [default %(defult)s]")
         args <- parser$parse_args()
 }

file calling source()

args$arg1 = "c" 
args$arg2 = "d"
source ("file_to_be_sourced.R")
print (args)

c, d