File connections are a way for R to interact with text files. They are created with the `file()` function, which takes the name of the file as an argument. The `file()` function also takes an `open` argument, which specifies the mode in which the file should be opened. The following are the possible values for the `open` argument:
- `r`: Open the file in read-only mode.
- `w`: Open the file for writing (and initialize a new file).
- `a`: Open the file for appending.
- `rb`: Open the file in read-only mode in binary mode.
- `wb`: Open the file for writing in binary mode.
- `ab`: Open the file for appending in binary mode.
Once a file connection has been created, it can be used to read from or write to the file. To read from a file connection, you can use the `readLines()` function. To write to a file connection, you can use the `writeLines()` function.
When you are finished with a file connection, you should close it. This can be done with the `close()` function.
Here is an example of how to use file connections to read from a text file:
con <- file("foo.txt")
open(con, "r")
data <- readLines(con)
close(con)
This code will open the file `foo.txt` in read-only mode, read the contents of the file into the variable `data`, and then close the file.
