#!/usr/bin/bash
from random import random


# You have a bookstore, with a finite capacity.
def generate_store(capacity=100):
    return generate_books(number=capacity)


# In each set of books, some are worth something and others aren't.
def generate_books(quality=0.25, number=20):
    return [random() < quality for _ in range(number)]


# We need to display what the stuff looks like, right?
def print_books(store):
    print("".join("*" if book else "." for book in sorted(store)))


# Here's your store.
capacity = 100
store = generate_store(capacity)

# How are we looking?
print_books(store)

# On your first day, all the good books get bought.
store = [book for book in store if not book]

# Oh, we need to replace them now.
replacements = capacity - len(store)
store.extend(generate_books(number=replacements))

# How are we looking?
print_books(store)

# Great, all the good books get bought.
store = [book for book in store if not book]

# Replacing them again...
replacements = capacity - len(store)
store.extend(generate_books(number=replacements))

# How are we looking now?
print_books(store)