Read from txt file in Praat - “File not recognized” error

Praat is a great tool for analysing speech data but lately I came across a frustrating problem. While trying to open a txt file (vector of numbers) in Praat I would get the following error message:
File not recognized. File not finished.
Praat-read-from-file-error
After consulting my fellow PhD students I discovered that what I was missing was a header enabling Praat to read txt files.
The simplest way to fix this error is to add the following header to a text file using your favourite text editor:

However, if you want to automate the process then scripting can save you a lot of time. That’s why I created a function (txt2praat.R) appending this header to the original text file and saving the output to a new text file.

You can use the function in the following way:
txtfile <- file.choose()
txt2praat(txtfile, testfile-modified)

These commands should create a txt file (testfile - modified) appended with the short header. New file can be then opened in Praat without the error message.