process_file {xfun}

Read a text file, process the text with a function, and write the text back

Description

Read a text file with the UTF-8 encoding, apply a function to the text, and write back to the original file if the processed text is different with the original input.

Usage

process_file(file, fun = identity, x = read_utf8(file))

sort_file(..., fun = sort)

Arguments

file

Path to a text file.

fun

A function to process the text.

x

The content of the file.

...

Arguments to be passed to process_file().

Details

sort_file() is an application of process_file(), with the processing function being sort(), i.e., it sorts the text lines in a file and write back the sorted text.

Value

If file is provided, invisible NULL (the file is updated as a side effect), otherwise the processed content (as a character vector).

Examples

f = tempfile()
xfun::write_utf8("Hello World", f)
xfun::process_file(f, function(x) gsub("World", "woRld", x))
xfun::read_utf8(f)  # see if it has been updated
file.remove(f)