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
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