Read last lines of file with Python deque

October 11, 2017

Python collections.deque is a fast FIFO that does not require thread locking as the more sophisticated queue.

Use deque to read the last line of files as follows.

from pathlib import Path
from collections import deque

fn = Path('myfile.txt')

with fn.open('r') as f:
    last = deque(f, 1)[0]

By changing 1 the last N lines of the file may be read and indexed.