CODEWITHSUNDEEP
rfunction
Jeremy Yeo
Jeremy Yeo

Reputation: 493

R functions with optional arguments to save file

I'm trying to create a user defined function in R with an optional argument to save the plot as a pdf. I have the required parameter to default to FALSE. If TRUE, then save to pdf with filename.pdf. Have I gotten some syntax wrong:

seeplot <-function (save=FALSE) {
x <- seq(1,10,1)
y <- x^2
plot (x,y,type="l")
if (save==TRUE) pdf(file="save")
}

Thanks.

Upvotes: 1

Views: 424

Answers (1)

Tyler Rinker
Tyler Rinker

Reputation: 109874

I think it's from not reading ?pdf carefully that you're experiencing troubles. I'd let you struggle a bit (as struggle is good, shoot I often battle R) but I think maybe the logical save approach is not the best so I'll chime in. Here's 3 mistakes I see:

  1. You call pdf but then never plot after that
  2. You never say dev.off
  3. There's no file extension to the pdf

Here is your function fixed:

seeplot <-function (save=FALSE) {
    x <- seq(1,10,1)
    y <- x^2
    plot (x,y,type="l")
    if (save) {
        pdf(file="save.pdf")
        plot (x,y,type="l")
        dev.off()
    }
}

But may I recommend supplying a file name instead of a logical save. This allows the user to name the file as they please:

seeplot <-function (file=NULL) {
    x <- seq(1,10,1)
    y <- x^2
    plot (x,y,type="l")
    if (!is.null(file)) {
        pdf(file=file)
        plot (x,y,type="l")
        dev.off()
    }
}

Upvotes: 9

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