Check in R if a Directory Exists and Create if It doesn’t (Programming Example)

 

This R tutorial explains how to check for the existence of a directory and create a new directory if it doesn’t exist.

The article contains the following sections:

Let’s dive right into the examples…

 

Store Working Directory

Before we can start with the examples, it is helpful to store the working directory you want to use in a new data object. Let’s do this:

main_dir <- "C:/Users/ ... Your Path ... /main_dir"   # Set your working directory

The previous R code stored our main working directory in the data object main_dir. Note that you have to replace the … Your Path … with your own directory path.

Let’s have a look on our example directory:

 

main directory

Figure 1: Example Directory with One Already Existing Sub-directory.

 

As you can see based on Figure 1, our example directory contains one sub-directory with the name subdir_example.

 

Check for Existence of Sub-directory

In this section, we will try to create a new directory, but only in case the directory name does not exist yet. First, we need to specify the name of the sub-directory that we want to create. Let’s assume that we want to create the folder subdir_example (i.e. a folder with the same name as the folder that already exists).

sub_dir_exists <- "subdir_example"                    # Name of already existing folder

With the following R code, we can check for the existence of this directory and create it in case it doesn’t exist:

dir.create(file.path(main_dir, sub_dir_exists))       # Try to create already existing folder
# Warning message:
#   In dir.create(file.path(main_dir, sub_dir_exists)) :
#   'C:\Users\ ... Your Path ... \main_dir\subdir_example' already exists

The RStudio console returns a warning message:

In dir.create(file.path(main_dir, sub_dir_exists)) :
‘C:\Users\ … Your Path … \main_dir\subdir_example’ already exists

If you see this warning message, you know that a file with your specified name already exists and that no new folder was created.

 

Create New Sub-directory

If we want to create a new sub-directory, we need to specify a new name that does not exist yet:

sub_dir_new <- "subdir_new"                           # Name of new folder

Now, we can apply exactly the same R syntax as in the previous section…

dir.create(file.path(main_dir, sub_dir_new))          # Create new folder

…but this time we do not get a warning – The new folder was successfully created:

 

new sub-directory created by r programming language

Figure 2: Example Directory with New Sub-directory.

 

Video Tutorial & Further Resources

On my YouTube channel, I have published a live programming tutorial, which contains the examples of this article. In case you are interested, you can find the video tutorial below:

 

 

Also, you might want to have a look at the other R tutorials of this homepage. You can find some recommended tutorial below:

This page explained how to create a directory in RStudio in case it does not exist yet. If you have any further questions, please let me know in the comments below.

 



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