If file exists in folder read it else skip the processing part

Question

I am reading in several *.csv, where the names and paths are determined at runtime.

However sometimes there are files with do not exist. For this file I need kind of exception handling.

Currently I am reading in my files with:

    companyFileName <- paste("C://Users//Prices//",companiesIsin,".csv") df <- read.csv(gsub(" ","", companyFileName, fixed=TRUE), header = TRUE, sep = ";",stringsAsFactors=FALSE) 

When the file does not exist in the folder I am getting an error. Is there something like exception handling in R?

I appreciate your reply!

Answer 1

You can check if a file exists using the function file.exists. So you might check for file existence before trying to read it in to avoid an error, e.g.

if (file.exists(companyFileName))    df <- read.csv(gsub(" ","", companyFileName, fixed=TRUE), header = TRUE, sep = ";",stringsAsFactors=FALSE) 

EDIT: You may also simplify the creation of the path and use read.csv2 for the ; separator. This makes it a bit more readable.

f <- paste0("C://Users//Prices//",companiesIsin,".csv") if (file.exists(f))   df <- read.csv2(f, TRUE, stringsAsFactors=FALSE) 

Answer 2

This code can be used to check if a file exits in a folder with date format as TRUE or FALSE.

setwd("D:\\FILEFOLDER")  datafile<-file.exists(paste0('DATA_',format(Sys.Date()-1,'%Y%m%d'),'.gz'))  voicefile<-file.exists(paste0('VOICE_TEXT_',format(Sys.Date()-1,'%Y%m%d'),'.gz'))