I want to repeat a function indefinitely

Question

I am working through some exercises on python and my task is to create a program that can take a number, divide it by 2 if it is an even number. Or it will take the number, multiply it by 3, then add 1. It should ask for an input and afterwards it should wait for another input.

My code looks like this, mind you I am new to all this.

print('Please enter a number:')

def numberCheck(c):
    if c % 2 == 0:
        print(c // 2)
    elif c % 2 == 1:
        print(3 * c + 1)

c = int(input())
numberCheck(c)

I want it to print "Please enter a number" only once. but after running I want it to wait for another number. How would I do this?

I tried a for loop but that uses a range and I don't want to set a range unless there is a way to do it to infinity.

So, I am thinking about your current predicament, but I am also curious. Is there a reason you are using floor division? — MatthewS, Jan 17 '21 at 18:19
`while True` is your friend. Also since you seem to be a Python beginner, may I suggest to use PEP8 naming style? ie no `camelCase` names but rather `snake_case` — ThiefMaster, Jan 17 '21 at 18:20
I don't know, it is only chapter 3 of the book and I am doing as told lol — B3y0ndD34th, Jan 17 '21 at 18:31
If you are using Python 3.9 or above, use `while (c:= int(input()): numberCheck(c)` to get an infinite loop — Joe Ferndz, Jan 18 '21 at 09:11
The linked question is not really a duplicate, it asks specifically for a possibility of an infinite loop using a `for` statement, while this one is about infinite loops in general. A better duplicate target would be https://stackoverflow.com/questions/24335680/how-can-i-make-this-repeat-forever. — mkrieger1, Apr 19 '22 at 23:01

Cryton Andrew · Answer 1 · 2021-01-18T09:05:05.990

1

So my understanding is you want the function to run indefinitely. this is my approach, through the use of a while loop

print("Enter a number")

while True:
  c = int(input(""))
  numberCheck(c)

edited Jan 18 '21 at 09:05

answered Jan 17 '21 at 18:23

Cryton Andrew

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Minor nit: It should be `while True:` (Capital T) – Slakker Jan 17 '21 at 18:24
@Slakker well, it's not minor! – Mushif Ali Nawaz Jan 17 '21 at 18:25
Worked perfect thank you. When I tried a while loop I put the while True in the wrong spot because I did not get the expected result, but now I do see why this would work, – B3y0ndD34th Jan 17 '21 at 18:27
why do you say it's not memory efficient? Memory should not accumulate here if i understand garbage collection correctly – Chris_Rands Jan 17 '21 at 18:27
That was a misunderstanding from me – Cryton Andrew Jan 18 '21 at 09:04

score 1 · Accepted Answer · edited Apr 19 '22 at 22:59

1

If you want to run an infinite loop, that can be done with a while loop.

print('Please enter a number:')

def numberCheck(c):
        if c % 2 == 0:
            print(c // 2)
        elif c % 2 == 1:
            print(3 * c + 1)
            
while True:
    c = int(input())
    numberCheck(c)

edited Apr 19 '22 at 22:59

mkrieger1

19,194
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answered Jan 17 '21 at 18:24

Devansh Srivastav

51
4

score 0 · Answer 3 · answered Jan 17 '21 at 18:23

0

You could use a while loop with True:

while True:
    c = int(input())
    numberCheck(c)

answered Jan 17 '21 at 18:23

Mureinik

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I want to repeat a function indefinitely

3 Answers3

Linked