Temporary directory and files
Firstly let’s create a folder to work with in a temporary directory. Look for details on how to work with temporary files in R in my post When do you need temporary directory and files in R and how to use them.
tempfile() does not create any files, it generates a random file name, what is unique for the current R session. By default
tempfile() generates file name in R temporary directory.
Exploring file system
mydirname variable we have a file path where we can create a file. Now there is nothing. Let’s check it with function
file.exists() and the content of the temporary directory with function
Creating of a directory
Next we really touch our file system and create desired directory.
And check it again:
- content of parent directory;
- modification time.
More listings including R system files
Let’s inspect files from one of installed R-packages. A command
system.file() returns full path of files from installed packages. We use it to get a file path of
Next we list content of this folder.
We can check content of any subdir. For example “demo” folder.
In some situations you would prefer full names:
Constructing of file names in R
What is a file name? It is a character string. Wrong. It is a system-specific character string.
file.path() creates system-specific file names.
Note about Windows
file.path() put slashes as separator, when we used to backslash in Windows (for example
C:\Program Files\R\R-3.3.1)? There is even a special note on it in
file.path’s help page:
The components are by default separated by ‘/’ (not ‘\’) on Windows.
Surprisingly DOS and Windows supported slash as file path separator from the beginning. So in most cases one can use as slash, so backslash in Windows.