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update birthdayparadox.py

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cheeks 2025-03-13 19:38:43 +00:00
parent 210cf4418c
commit 74ceea588a
1 changed files with 48 additions and 2 deletions
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birthdayparadox.py
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@ -1,4 +1,4 @@
""" Birthday Paradox Simulation, by Al Sweigart al@inventwithpython.com
"""Birthday Paradox Simulation, by Al Sweigart al@inventwithpython.com
Explore the surprising possibilities of the "Birthday Paradox".
More info at https://en.wikipedia.org/wiki/Birthday_problem
View this code at https://nostarch.com/big-book-small-python-projects
@ -6,6 +6,7 @@ Tags: short, math, simulation"""
import datetime, random
def getBirthdays(numberOfBirthdays):
"""Returns a list of number random date objects for birthdays."""
birthdays = []
@ -20,4 +21,49 @@ def getBirthdays(numberOfBirthdays):
birthdays.append(birthday)
return birthdays
def getMatch(birthdays):
"""Returns the date object of a birthday that occurs more than once
in the birthdays list."""
if len(birthdays) == len(set(birthdays)):
return None #All birthdays are unique, so return None.
# Compare each birthday to every other birthday:
for a, birthdayA in enumerate(birthdays):
for b, birthdayB in enumerate(birthdays[a + 1 :]):
if birthdayA == birthdayB:
return birthdayA # Return the matching birthday
# Display the intro:
print('''Birthday Paradox, by Al Sweigart al@inventwithpython.com
The Birthday Paradox shows us that in a group of N people, the odds
that two of them have matching birthdays is surprisingly large.
This program does a Monte Carlo simulation (that is, repeated random
simulations) to explore this concept.
(It's not actually a paradox, it's just a surprising result.)
''')
# Set up a tuple of month names in order:
MONTHS = ('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec')
while True: # Keep asking until the user enters a valid amount.
print('How many birthdays shall I generate (Max 100)')
response = input('> ')
if response.isdecimal() and (0 < int(response) <= 100):
numBDays = int(response)
break # User has entered a valid amount
print()
# Generate and display birthdays:
print('Here are', numBDays, 'birthdays:')
birthdays = getBirthdays(numBDays)
for i, birthday in enumerate(birthdays):
if i != 0:
# Display a comma for each birthday after the first birthday.
print(', ', end='')
monthName = MONTHS[birthday.month - 1]
dateText = '{} {}'.format(monthName, match.day)
print(dateText, end='')
print()
print()