Command Line Arguments in R Programming Language

Here’s the translated code and explanation in R, formatted in Markdown suitable for Hugo:

Our first program will print the classic “hello world” message. Here’s the full source code.

# Command-Line Arguments

# Command-line arguments are a common way to parameterize execution of programs.
# In R, we can access command-line arguments using the commandArgs() function.

# Get all command-line arguments, including the script name
args_with_script <- commandArgs(trailingOnly = FALSE)

# Get only the arguments passed to the script
args_without_script <- commandArgs(trailingOnly = TRUE)

# You can get individual args with normal indexing
if (length(args_without_script) >= 3) {
  arg <- args_without_script[3]
} else {
  arg <- "Not enough arguments provided"
}

# Print the results
print(args_with_script)
print(args_without_script)
print(arg)

To experiment with command-line arguments in R, you can save this script to a file (e.g., command_line_arguments.R) and run it from the command line using Rscript.

$ Rscript command_line_arguments.R a b c d

This will output something like:

[1] "/usr/local/bin/Rscript"                            
[2] "--vanilla"                                         
[3] "command_line_arguments.R"                          
[4] "a"                                                 
[5] "b"                                                 
[6] "c"                                                 
[7] "d"                                                 
[1] "a" "b" "c" "d"
[1] "c"

Note that the exact output may vary depending on your R installation and operating system.

In R, we don’t typically build binary executables like in compiled languages. Instead, R scripts are interpreted and can be run directly using the Rscript command or within an R environment.

Next, we’ll look at more advanced command-line processing using packages like optparse or argparse, which provide functionality similar to command-line flags in other languages.