Deleting Files in R based on their Names

[omario]

I am working with the R programming language.

I recently learned how to delete a file having a specific name from the working directory:

#Define the file name that will be deleted
fn <- "foo.txt"

#Check its existence
if (file.exists(fn)) {
    #Delete file if it exists
    file.remove(fn)
}

[1] TRUE

My Question: Is it possible to delete files based on whether the file name contains a specific combination of letters (i.e. LIKE 'fo%' )? This way, all files in the working directory starting with the letters "fo" will be deleted.

What I tried so far:

I thought of a way where I could first create a list of all files in the working directory that I want to delete based on their names:

# create list of all files in working directory 
a = getwd()
path.to.csv <- a
files<-list.files(path.to.csv)
my_list = print(files)  ## list all files in path

#identify files that match the condition
to_be_deleted = my_list[grepl("fo",unlist(my_list))]

Then, I tried to deleted this file using the command used earlier:

if (file.exists(to_be_deleted)) {
    #Delete file if it exists
    file.remove(to_be_deleted)
}

This returned the following message:

[1] TRUE TRUE TRUE TRUE TRUE TRUE
Warning message:
In if (file.exists(to_be_deleted)) { :
  the condition has length > 1 and only the first element will be used

Does anyone know if I have done this correctly? Suppose if there were multiple files in the working directory where the names of these files started with "fo" - would all of these files have been deleted? Or only the first file in this list?

Can someone please show me how to do this correctly?

Thanks!

[FJCC]

The list.files() function has a pattern argument that you can use to select files. For example, to delete all files whose name ends in csv from the current directory

FILES <- list.files(pattern = "csv$")
file.remove(FILES)

[omario]

@ FJCC : thank you for your reply! Would this code above remove all files that contain the letters "csv"?

For instance, would the following files be deleted?

"my_csv.txt"

"my_txt.csv"

Using the code you provided:

FILES <- list.files(pattern = "csv$")
file.remove(FILES)

Would both of these files be deleted?

Thank you so much!

[FJCC]

As written, the code looks for files whose name ends with csv. The $ represents the end of the name. If you remove the $, the function will find files with csv anywhere in the name. The pattern argument is a regular expression. Learning regular expressions is worth the trouble.