Parallel Python

import glob
import sys
import operator

from functools import reduce
from pathlib import Path
from concurrent.futures import ProcessPoolExecutor

def count_lines_in_file(file):
    """
    Calculate the number of lines of text in a single file
    """
    text = file.read_text()
    lines = text.split("\n")
    return len(lines)

if __name__ == "__main__":
    # get all of the names of the plays from the command line
    files = sorted(Path("shakespeare").glob("*"))

    with ProcessPoolExecutor() as pool:
        # map the count_lines function against all of the
        # files listed in "filenames"
        play_line_count = pool.map(count_lines_in_file, files)
        
        # convert it to a list as we need to use the result in two places.
        play_line_count = list(play_line_count)

        for f, count in zip(files, play_line_count):
            print(f"{f} has {count} lines")

    total = reduce(operator.add, play_line_count)
    print(f"The total number of lines is {total}.")

python countlines.py shakespeare

shakespeare/README has 3 lines
shakespeare/allswellthatendswell has 4516 lines
shakespeare/antonyandcleopatra has 5999 lines
shakespeare/asyoulikeit has 4123 lines
shakespeare/comedyoferrors has 2938 lines
shakespeare/coriolanus has 5837 lines
shakespeare/cymbeline has 5486 lines
shakespeare/hamlet has 6046 lines
shakespeare/juliuscaesar has 4108 lines
shakespeare/kinglear has 5526 lines
shakespeare/loveslabourslost has 4336 lines
shakespeare/macbeth has 3877 lines
shakespeare/measureforemeasure has 4338 lines
shakespeare/merchantofvenice has 3884 lines
shakespeare/merrywivesofwindsor has 4449 lines
shakespeare/midsummersnightsdream has 3116 lines
shakespeare/muchadoaboutnothing has 4064 lines
shakespeare/othello has 5425 lines
shakespeare/periclesprinceoftyre has 3872 lines
shakespeare/romeoandjuliet has 4767 lines
shakespeare/tamingoftheshrew has 4149 lines
shakespeare/tempest has 3400 lines
shakespeare/timonofathens has 3974 lines
shakespeare/titusandronicus has 3768 lines
shakespeare/troilusandcressida has 5444 lines
shakespeare/twelfthnight has 4018 lines
shakespeare/twogentlemenofverona has 3606 lines
shakespeare/winterstale has 4644 lines
The total number of lines is 119713.