8c-challenge-simulate-a-coin-toss-experiment.py

# 8.8 - Challenge: Simulate a Coin Toss Experiement
# Alternative solution to challenge using functions


# Simulate the results of a series of coin tosses and track the results

# This one is tricky to structure correctly. Try writing out the logic before
# you start coding. Some additional pointers if you're stuck:
# 1. You will need to use a `for` loop over a range of trials.
# 2. For each trial, first you should check the outcome of the first flip.
# 3. Make sure you add the first flip to the total number of flips.
# 4. After the first toss, you'll need another loop to keep flipping while you
#    get the same result as the first flip.

import random


def single_trial():
    """Simulate repeatedly flipping a coin until both heads and tails are seen."""
    # This function uses random.randint() to simulate a single coin toss.
    # randint(0, 1) randomly returns 0 or 1 with equal probability. We can
    # use 0 to represent heads and 1 to represent tails.

    # Flip the coin the first time
    flip_result = random.randint(0, 1)
    # Keep a tally of how many times the coin has been flipped. We've only
    # flipped once so the initial count is 1.
    flip_count = 1

    # Continue to flip the coin until randint(0, 1) returns something
    # different than the original flip_result
    while flip_result == random.randint(0, 1):
        flip_count = flip_count + 1

    # The last step in the loop flipped the coin but didn't update the tally,
    # so we need to increase the flip_count by 1
    flip_count = flip_count + 1
    return flip_count


def flip_trial_avg(num_trials):
    """Calculate the average number of flips per trial over num_trials total trials."""
    total = 0
    for trial in range(num_trials):
        total = total + single_trial()
    return total / num_trials


print(f"The average number of coin flips was {flip_trial_avg(10_000)}")