Making a collatz program automate the boring stuff

Question

I\'m trying to write a Collatz program using the guidelines from a project found at the end of chapter 3 of Automate the Boring Stuff with Python. I\'m using python 3.

Answer 1

I have added the try and except like this (with a break)

def collatz(number):
if number %2 == 0:
    print(number//2)
    return number//2
elif number %2 == 1:
    print(3 * number + 1)
    return 3 * number + 1

n = input("Give me a number: ")

while n != 1:
    try:
        isinstance(n, int)
        n = collatz(int(n))
    except:
        print('Error: Invalid argument.')
        break

Answer 2

I think that this solution may be even simpler for learners than the accepted one:

def collatzSequence(number):
    if (number % 2 == 0): # if it's even
        number = number // 2
    else:                 # if it's odd
        number = number * 3 + 1
    print (number)
    return (number)

n = int(input('Enter a number: '))
while (n != 1):
    n = collatzSequence(n)

The result will something like this:

Enter a number: 5
16
8
4
2
1

Answer 3

def collatz(num): 
    if num % 2: 
        return 3 * num + 1
    else:
        return num // 2

while True:
    try:
    number = int(input('Enter a positive integer.'))  
    if number <= 0: 
        continue
    break
except ValueError: 
    continue


while number != 1:
    number = collatz(number)
    print(number)

Answer 4

Every solution on this thread is missing one thing: if the user inputs "1" the function should still run the computations of the Collatz sequence. My solution:

def collatz(number):
    while number == 1:
        print("3 * " + str(number) + " + 1 = " + str(3*number+1))
        number = 3*number+1 ##this while loop only runs once if at all b/c at end of it the value of the variable is not equal to 1
    else:
        while number != 1:
            if number % 2 == 0:
                print(str(number) + ' // 2 = ' + str(number//2))
                number = number//2
            else:
                print("3 * " + str(number) + " + 1 = " + str(3*number+1))
                number = 3*number+1

 print('Please input any integer to begin the Collatz sequence.')

while True:
    try:
        number = int(input())
        collatz(number)
        break
    except ValueError:
        print('please enter an integer')

Answer 5

def collatz(number):
    while number != 1:
        if number % 2 == 0:
            number = number // 2
            print(number)

        elif number % 2 == 1:
            number = number * 3 + 1
            print(number)

try:
    num = int(input())
    collatz(num)
except ValueError:
    print('Please use whole numbers only.')

This is what I came up with on my own and based solely on what I've learned from the book so far. It took me a little bit but one of the tools I used that was invaluable to me finding my solution and has also been invaluable in learning this content is the python visualizer tool at: http://www.pythontutor.com/visualize.html#mode=edit

I was able to see what my code was doing and where it was getting hung up and I was able to continually make tweaks until I got it right.

Answer 6

import sys

def collatz(number):
if number % 2 == 0:
    result = number // 2
    print (result)

elif number % 2 == 1:
    result = number * 3 + 1
    print (result)

while result == 1:
    sys.exit

while result != 1:
    number = result
    collatz(number)

print ('Enter a number')

try:
    number = int(input())
    collatz(number)

except ValueError:
    print('Please enter a valid integer')