collatz sequence (snippet)

Python example 'collatz sequence'

Functions in program:

def collatz_conjecture(n):

Modules used in program:

import sys

collatz sequence

Python beginners example: collatz sequence

#!/usr/bin/python
# -*- coding: utf-8 -*-

import sys

# Collatz conjecture
# is a series of numbers
# where the orignal number is manipulated, until
# one is obtained
# if n is even n // 2 is the next number
# else n * 3 
# No matter what the value of n we'll,
# always reach 1.
# See: https://en.wikipedia.org/wiki/Collatz_conjecture

# Collatz series generator
def collatz_conjecture(n):
    if n < 1: 
        raise Exception("\n  Expected a value greater than 1")

    while n != 1:
        if n % 2 == 0:
            n = n // 2
        else: n = 3*n + 1
        yield n

# If n will be negative then
# sequence will be infinite

# Interface
# Test/Play
i = 0
while True:
    if raw_input("\n[%i] Continue[Y/n]?: " % i).strip().lower() == "y":
        for v in collatz_conjecture(int(raw_input("N?: "))):
            print("  > " + str(v))
        i += 1
    else:
        print("\nSee you soon!")
        sys.exit(0)

Useful links

Learn Python: https://pythonbasics.org
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