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 3.4.0. Here's the project outline:

Write a function named collatz() that has one parameter named number. If number is even, then collatz() should print number // 2 and return this value. If number is odd, then collatz() should print and return 3 * number + 1. Then write a program that lets the user type in an integer and that keeps calling collatz() on that number until the function returns the value 1.

The output of this program could look something like this: Enter number: 3 10 5 16 8 4 2 1

I am trying to make a function that uses if and elif statements within a while loop. I want the number to print, and then return to the beginning of the loop and reduce itself to one using the collatz sequence, with each instance of a resulting number being printed as it goes through the loop. With my current code, I'm only able to print the first instance of the number, and that number does not go through the loop after that. Here's my code:

#collatz

print("enter a number:")
try:
    number = (int(input()))
except ValueError:
          print("Please enter a valid INTEGER.")


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

        if number % 2==0:
            number = (number//2)
            #print(number)
            return (print(int(number)))

        elif nnumber % 2==1:
            number = (3*number+1) 
            #print(number)
            return (print(int(number)))

        continue


collatz(number)

Answer 1

def collatz(number):
    while number != 1:
        if number %2==0:
            number = number//2
            yield number
        elif number %2 ==1:
            number=number*3 +1
            yield number

while True:
    try:
        for n in collatz(int(input('Enter number:'))):
            print(n)
        break
    except ValueError:
        print('Please enter an integer')

The extra while True loop will help the program to continue functioning after the user inputs a non-integer.

Answer 2

def collatz(number): 
    if number%2==0:    
        return number//2
    elif number%2==1:
        return number*3+1
step=1 #counter variable for amusement and seeing how many steps for completion.
try: #in case of ValueError   
    number=int(input('Enter a Number for Collatz Sequencing:')) 
    while collatz(number)!=1:    
        print(collatz(number))
        number=int(collatz(number))
        if collatz(number)!=1: 
            print('Calculating step ' + str(step) + '.')
            step=step+1
        else:
            print ('Calculating step ' +str(step) + '.')
            print('1 Has Been Reached.')
except ValueError: 
     print('Enter an Integer please:')