making commandargs comma delimited or parsing spaces

Question

I'm trying to run R from the command line using command line arguments. This includes passing in some filepaths as arguments for use inside the script. It all works most of the time, but sometimes the paths have spaces in and R doesn't understand. I'm running something of the form: ``` R CMD BATCH --slave "--args inputfile='C:/Work/FolderWith SpaceInName/myinputfile.csv' outputfile='C:/Work/myoutputfile.csv'" RScript.r ROut.txt ``` And R throws out a file saying ``` Fatal error: cannot open file 'C:\Work\FolderWith': No such file or directory ``` So evidently my single quotes aren't enough to tell R to take everything inside the quotes as the argument value. I'm thinking this means I should find a way to delimit my `--args` using a comma, but I can't find a way to do this. I'm sure it's simple but I've not found anything in the documentation. The current script is very basic: ``` ca = commandArgs(trailingOnly=TRUE) eval(parse(text=ca)) tempdata = read.csv(inputFile) tempdata$total = a…

Accepted Answer

Using `eval(parse())` is probably not the best and most efficient way to parse command line arguments. I recommend to use a package like the `optparse` to do the parsing for you. Parsing command line args has already been solved, no need to reimplement this. I could imagine that this solves your problems. Although, spaces in path names are a bad idea to begin with.

Alternatively, you could take a very simple approach and pass the arguments like this:

```
R CMD BATCH --slave arg1 arg2
```

Where you can retrieve them like:

```
ca = commandArgs(TRUE)
arg1 = ca[2]
arg2 = ca[3]
```

This avoids the `eval(parse` which I think is causing the issues. Finally, you could try and escape the space like this:

```
R CMD BATCH --slave "C:/spam\ bla"
```

You could also give `Rscript` a try, `R CMD BATCH` seems to be less favored than `Rscript`.

making commandargs comma delimited or parsing spaces

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