How to prevent R from stopping when it can't find the file to open?

Question

My R code is trying to open a RDS file in a for loop as follows:

for(i in 1:run_loops){
    source("./scripts/load_data.R")
    model <- readRDS(file=paste(model_directory,"/",modelname,".Rds", sep="")) #STOPS-HERE!!!
    source("./scripts/prediction.R")
  }

R stops when there is no model file.
How do I get it to move to the next iteration instead of stopping?

P.S. modelname variable changes each time load_data.R is sourced.

Does this answer your question? [How to write trycatch in R](https://stackoverflow.com/questions/12193779/how-to-write-trycatch-in-r) — starja, Dec 14 '20 at 12:29
@starja it helps indirectly, however file.exists() is exactly what I was looking for. Thanks. — uguros, Dec 14 '20 at 13:48

Steffen · Answer 1 · 2020-12-14T12:34:48.287

2

This should do the trick:

for(i in 1:run_loops) {
  tryCatch(
    expr = {
      source("./scripts/load_data.R")
      model <-
        readRDS(file = paste(model_directory, "/", modelname, ".Rds", sep = "")) #STOPS-HERE!!!
      source("./scripts/prediction.R")
    },
    error = function(e) {
      print(paste0(i, ' not done'))
    }
  )
}

edited Dec 14 '20 at 12:34

answered Dec 14 '20 at 12:28

Steffen

206
1
7

score 1 · Accepted Answer · answered Dec 14 '20 at 12:29

1

You can use file.exists

file_name <- paste0(model_directory,"/",modelname,".Rds")
if(file.exists(file_name)) {
  #do something
} else {
  #do something else
}

answered Dec 14 '20 at 12:29

Ronak Shah

377,200
20
156
213

How to prevent R from stopping when it can't find the file to open?

2 Answers2