[FIXED] How to read a portion of a file in Elixir (or Erlang)?

Issue

How can we read only a selected portion of a file?

Like this: Read(file, start, length)

Solution

You can use :file.position/2 and :file.read/2.

With:

$ seq 10 > 10.txt

and code:

{:ok, file} = :file.open("10.txt", [:read, :binary])
:file.position(file, 5)
IO.inspect :file.read(file, 10)

The output is:

{:ok, "\n4\n5\n6\n7\n8"}

That's 10 bytes starting at the 6th byte.

Answered By - Dogbert

Answer Checked By - Senaida (PHPFixing Volunteer)