Save multiple plots as individual PDFs with unique names in R - r

Question

I have a function that creates a plot and saves it as a pdf file. I plan on running this function in a loop for 100+ columns of a dataset. My question is how to make each pdf file uniquely named so it doesnt overwrite the previous file every time a new one is made. I tried to make it work with C integer format
pdf(file = "~/PTY/Data/ROC Curves/ROC%03d.pdf", onefile = F, width = 7, height = 7)
with the intended outcome of titling each plot ROC001, ROC002... but it still overwrites each new one as ROC001.
createROC <- function(x) {
ROCtable <- createNAtable(x) #create dataset w/out NAs
x_NA <-x[!is.na(x)] #create analyte vector w/out NAs
#create ROC variable
newROC <- rocit(score = x_NA, class = ROCtable$DSM, negref = "0", method = "non")
#create pdf
pdf(file = "~/PTY/Data/ROC Curves/ROC%03d.pdf", onefile = F, width = 7, height = 7)
#create ROC plot
plot(newROC, legend = F)
dev.off()
}
My function takes a vector (data1$IL6, data1$age, etc) as an input. Ideally, I would be able to title each plot after the input (IL6, age, etc).
Thank you ahead of time for your help

Answer 1

The problem is that you are opening and closing the graphics device with each plot, and the counter resets at 001 each time. You need one call to pdf(), followed by all of your calls to plot(), followed by dev.off(), like so:
# Some data with named columns
df <- data.frame(a = 1:10, b = 11:20, c = 21:30)
# A plotting function without `pdf()` and `dev.off()`
create_plot <- function(x, main) {
plot(x, main = main)
}
# Open graphics device
pdf(file = "filename-%03d.pdf", onefile = FALSE)
# Apply plotting function to each column of `df` in a loop
for (j in 1:3) {
create_plot(df[, j], names(df)[j])
}
# Close graphics device
dev.off()
This should generate filename-001.pdf, filename-002.pdf, and filename-003.pdf in your working directory.