You can use the following basic syntax to check if a file exists in your current working directory in R:

file.exists('my_data.csv')

This function will return TRUE if the file exists or FALSE if it does not.

You can also use an if else statement to read a file into R only if it exists:

data <- 'my_data.csv'

if(file.exists(data)){  df <- read.csv(data)} else {  print('Does not exist')}

The following example shows how to use these functions in practice.

Example: Check if File Exists in R

Suppose my current in R is a folder called test_data with three CSV files:

I can use list.files() to list out the names of every file in the working directory:

#display the names of every file in current working directory
list.files()
[1] "my_data.csv"       "my_new_data.csv"   "some_old_data.csv"

I can use file.exists() to check if a given file exists in the current working directory:

#check if file 'my_data.csv' exists in current working directory
file.exists('my_data.csv')

[1] TRUE

The function returns TRUE, which tells us that the file ‘my_data.csv’ does indeed exist in the current working directory.

We can then use the following if else statement to import a file only if it exists:

#define file name
data <- 'my_data.csv'

#import file only if it exists
if(file.exists(data)){  df <- read.csv(data)} else {  print('Does not exist')}

#view contents of CSV file
df

  team points assists
1    A     14       4
2    B     26       7
3    C     29       8
4    D     20       3

Since the file exists, we’re able to import it successfully.

#define file name
data <- 'this_data.csv'

#import file only if it exists
if(file.exists(data)){  df <- read.csv(data)} else {  print('Does not exist')}

[1] "Does not exist"

We receive the message Does not exist”, which tells us that a file called this_data.csv does not exist in the current working directory.