Calculate the probability of atleast one match after x tries

probability.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# SPDX-License-Identifier: MIT
# 
""" Calculate the probability of atleast one match after x tries"""

from __future__ import print_function

import argparse
import sys


def probability(options):

	percent_value = float(options.percent)
	
	# Probability of getting a match after 1 try
	fractional_value = percent_value/100
	
	# Not a match after 1 try
	no_match_fractional_value = 1 - fractional_value	
	
	# No of tries
	num_tries = 0
	
	while True:
		# No matches after `num_tries` tries
		no_matches_fractional_value = no_match_fractional_value ** num_tries
		num_tries += 1
		
		# At least one match after `num_tries` tries
		one_match_fractional_value = 1 - no_matches_fractional_value
		one_match_percent_value = 100 * one_match_fractional_value
		rounded_match_percent_value = round(one_match_percent_value)
		
		print(f"Tries: {str(num_tries).rjust(3,'0')}; Probability: {rounded_match_percent_value}%")
		
		if rounded_match_percent_value >= 100: 
			break
	
	return ScriptRC.SUCCESS


def get_options():
	parser = argparse.ArgumentParser()
	
	parser.add_argument("-p", "--percent", action="store", help="Percentage value", type=float, required=True)
	
	return parser.parse_args()


class ScriptRC(object):
	"""Enum for script return codes"""
	SUCCESS = 0
	FAILURE = 1
	EXCEPTION = 2


class ScriptException(Exception): 
	pass


if __name__ == "__main__":
	# Get the options from the user
	options = get_options()
	
	# Run main script
	try:
		rc = probability(options)
	except Exception as e:
		rc = ScriptRC.EXCEPTION
	
	sys.exit(rc)