Python random lines from subfolders

Question

I have many tasks in .txt files in multiple sub folders. I am trying to pick up a total 10 tasks randomly from these folders, their contained files and finally a text line w

Answer 1

EDIT: On closer scrutiny this answer does not fit the bill. Reworking it led me to the reservoir sampling algorithm, which @Blckknght used in his answer. So ignore this answer.

Few ways of doing it. Here's one...

1. Get a list of all task files
2. Select one at random
3. Select a single line from that file at random
4. Repeat until we have the desired number of lines

The code...

import os
import random

def file_iterator(top_dir):
    """Gather all task files"""
    files = []
    for dirpath, dirnames, filenames in os.walk(top_dir):
        for filename in filenames:
            if not filename.endswith('.txt'):
                continue
            path = os.path.join(dirpath, filename)
            files.append(path)
    return files


def random_lines(files, number=10):
    """Select a random file, select a random line until we have enough
    """
    selected_tasks = []

    while len(selected_tasks) < number:
        f = random.choice(files)
        with open(f) as tasks:
            lines = tasks.readlines()
            l = random.choice(lines)
            selected_tasks.append(l)
    return selected_tasks


## Usage
files = file_iterator(r'C:\\Tasks')
random_tasks = random_lines(files)