I am a beginner in R. For example i have a function called w whose code is listed below:
w<-function(x){
a<-x+2
plot(a)
}
How can i add these arguments in the function so that
Export: a number equal to 0 if result should be allowed on screen and to 1 if the result should be printed in a text file.
Tfile: name of the text file where the results will be written to;
Gfile:name of the pdf file where the graph will be written to.
To include further arguments in a function, simply list them in function().
w <- function(x, export, tfile, gfile) {
a <- x + 2
if (export == 1) {
write.csv(a, file = tfile)
} else if (export == 0) {
pdf(file = gfile)
plot(a)
dev.off()
}
}
For more information on writing and debugging functions in R, see this article.
As the others have pointed out, just separate additional arguments with commas. You can have as many as you want.
w <- function(x, export, tfile, gfile)
Assigning values within the function definition allows them to have default arguments, so you can choose not to include them
w <- function(x, export = 0, tfile = "w.csv", gfile = "w.pdf")
I will add that a handy thing for plot functions (and many other functions) is the ellipsis ... construct, which basically means "any other relevant arguments". For instance, doing something like this allows you to optionally pass further graphical parameters to your plot (e.g. label names, title).
w <- function(x, ...){
a <- x + 2
plot(a, ...)
}
w(10, main="Main title")
w(15, type='l', col='red')
export takes values 1 and 0 rather than TRUE and FALSE. Also, your last example won't run since you haven't enclosed both the definition of a and the call to plot() in brackets; a will be undefined when you try to plot it.
FALSE and 0 are equivalent.
function(x,export,tfile,gfile)?