[R] Force argument to have quotes

[Nordlund, Dan (DSHS/RDA)]

Bert has suggested there are better ways to do what you want.  But if you want to continue down the path you have started and you want to decide whether to quote based on the variable Class, something like this might work for you  

myOptions <- with(myFunction1Vals, paste(Argument, ifelse(Class=='character',shQuote(Value), Value), sep = '=', collapse = ","))


Hope this helps,

Dan

Daniel Nordlund, PhD
Research and Data Analysis Division
Services & Enterprise Support Administration
Washington State Department of Social and Health Services

> -----Original Message-----
> From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Bert
> Gunter
> Sent: Tuesday, June 06, 2017 12:14 PM
> To: Doran, Harold
> Cc: r-help at r-project.org
> Subject: Re: [R] Force argument to have quotes
> 
> Harold:
> 
> As a general rule, if you are using eval(parse(...)) you are doing it
> poorly in R; cf
> 
> library("fortunes")
> fortune(106)
> 
> Why is something like this not suitable:
> 
> fun1 <- function(a1,a2,a3 = c("hi","by"))
> {
>    cat(a3,a1+a2,"\n")
> }
> 
> > fun1 (1,2)
> hi by 3
> > fun1(1,2, a3 = "whoopee")
> whoopee 3
> 
> ... or, if you want to include the function as an argument of a list:
> 
> > myArgs <- list(fun=fun1, arglist=list(a1=2, a2 =5, a3 = c("hi","by")))
> 
> For which you can do stuff like:
> 
> > do.call(myArgs[[1]],myArgs[-1][[1]])
> hi by 7
> 
> > arglist <- myArgs[-1][[1]][-3]
> > do.call(myArgs[[1]],c(arglist,a3 = "whoopee"))
> whoopee 7
> 
> etc. etc.
> See ?do.call
> 
> Cheers,
> Bert
> 
> 
> 
> Bert Gunter
> 
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
> 
> 
> On Tue, Jun 6, 2017 at 8:01 AM, Doran, Harold <HDoran at air.org> wrote:
> > I am writing a program where non-technical R users will read in a config file
> and the config file will then parse the arguments found within the config and
> pass them to respective functions. I'm having trouble (efficiently) writing a
> piece of code to retain quotation marks around the argument which requires
> it as input, as found in the example function below, myFuncton1.
> >
> > Below is a minimal, reproducible example of the issue with comments.
> >
> > ### This is a sample structure of the configuration file
> >
> > scoreConfig <- structure(list(Function = c("myFunction1", "myFunction1",
> "myFunction1",
> > "myFunction2", "myFunction2"), Argument = c("arg1", "arg2", "arg3",
> > "arg1", "arg2"), Value = c("5", "10", "Hello", "5", "10"), Class = c("numeric",
> > "numeric", "character", "numeric", "numeric")), .Names = c("Function",
> > "Argument", "Value", "Class"), class = "data.frame", row.names = c(NA,
> > -5L))
> >
> > ### Two sample functions, once of which requires a string
> > myFunction1 <- function(arg1, arg2, arg3 = c('Hello', 'Goodbye')){
> >         arg3 <- match.arg(arg3)
> >         result <- arg1 + arg2
> >         cat(arg3, result, '\n')
> >         }
> >
> >
> > myFunction2 <- function(arg1, arg2){
> >         result <- arg1 * arg2
> >         result
> >         }
> >
> >
> > ### Working Example.
> > ### myFunction2 works no problem
> > myFunction2Vals <- subset(scoreConfig, Function == 'myFunction2')
> > myOptions <- with(myFunction2Vals, paste(Argument, Value, sep = '=',
> collapse = ','))
> > eval(parse(text = paste( "myFunction2(", myOptions, ")" )))
> >
> >
> > ### myFunction1 fails
> > myFunction1Vals <- subset(scoreConfig, Function == 'myFunction1')
> > myOptions <- with(myFunction1Vals, paste(Argument, Value, sep = '=',
> collapse = ','))
> > eval(parse(text = paste( "myFunction1(", myOptions, ")" )))
> >
> > ### What I want is simply
> > myFunction1(arg1 = 1, arg2 = 2, arg3 = 'Hello')
> >
> > I'm curious if someone has a perspective on the most efficient way to
> automate this by using information provided in the 'Value" column, so
> perhaps conditional on that value it could wrap the name in quotes.
> >
> > I admit to running into a limit and am tapping out so to speak on the right
> way to do this.
> >
> > Thanks for any advice
> > Harold
> >
> > ______________________________________________
> > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.