I can't understand why it won't return True always, since the ''return True'' statement is outside the loop

Question

Assuming played_chicket and winning_chicket are 2 random lists wiht 4 elements each, what does this loop returns? I can't understand the logic behind it. Won't it return True always because the ''return True'' statement is outside the loop? I know it will return false if any of the elements are different but i can't see why. Can someone please, explain it to me?

def check_ticket(played_ticket, winning_ticket):
    # Check all elements in the played ticket. If any are not in the 
    #   winning ticket, return False.
    for element in played_ticket:
        if element not in winning_ticket:
            return False
     
    # We must have a winning ticket!
    return True

Answer 1

This is most likely because the first element in played_ticket is not in winning_ticket

Consider played_ticket = [0,1,2] and winning_ticket = [1,2]

Your first iteration will look like this:

    for element in played_ticket:
        # element = 0
        if element not in winning_ticket:
            # 0 is not in winning_ticket, so it will return false immediately
            return False

---

Your function as is will always return False or nothing (becomes None). You will need to edit the function to have a fallback return True:

def check_ticket(played_ticket, winning_ticket):
    # Check all elements in the played ticket. If any are not in the
    #   winning ticket, return False.
    for element in played_ticket:
        if element not in winning_ticket:
            return False
    # Here
    return True

So if every element is in the other list, it will return True

---

See this discussion if you would like to simplify your function

Answer 2

by turning winning ticket into a list you could invert the process checking if the element is True, return False if nothing is True:

def check_ticket(played_ticket, winning_ticket):
# Check all elements in the played ticket. If any are not in the 
#   winning ticket, return False.
    if any(element in winning_ticket for element in played_ticket):
        return True
    return False