为什么当我随机 select 一个要放入列表的数字时，它总是选择相同的起始数字？

Question

This is the code. I'm learning Python and I tried writing a Blackjack script that can calculate the odds of ending up with an X sized hand while having 21 or below. The code is supposed to keep appending random cards out of the deck until it reaches a set amount of cards. (I know decks aren't usually infinite, it's just an experiment)

If it goes over 21 before X amount of cards in hand it discards the hand and starts a new hand.

But for some reason every time it starts a new hand that hand list starts with the same first integer as all previous hands like this:

Can someone please explain to me what I'm doing wrong?

[8, 3, 2, 6, 2]
[8, 2, 3, 2, 5]
[8, 2, 2, 4, 3]
[8, 6, 2, 2, 2]
[8, 2, 2, 2, 7]
[8, 4, 5, 2, 2]
[8, 5, 2, 2, 2]
[8, 2, 2, 2, 6]
[8, 2, 2, 6, 3]
[8, 3, 6, 2, 2]
[8, 6, 2, 2]
total amount of hands: 1020
the percentage of 7 card hands that total 21 or less is 1 in 10.2

import random

card_deck = [2,3,4,5,6,7,8,9,10,11]

def blackjack_tracker(deck):

    hand = []
    trackers = 0
    count = 0
    ace = 0
    x = 0

    while trackers <10:

        if len(hand) < 7:
            hand.append(random.choice(deck))

            if len(hand) == 7 and sum(hand) <= 21:
                print(hand)
                hand.pop(all(hand))
                trackers += 1
                count += 1

            elif len(hand) == 7 and sum(hand) > 21:
                hand.pop(all(hand))
                count += 1
            



    print(hand)
    print('total amount of hands: {}'.format(count))
    print('the percentage of 7 card hands that total 21 or less is 1 in {}'.format(count/10))

blackjack_tracker(card_deck)

Answer 1

The code that you use for "it discards the hand and starts a new hand" is:

hand.pop(all(hand))

which doesn't discard the whole hand (the meaning of this expression is explained later).

You should use either:

hand.clear()

or

hand = []

Integesting is the meaning of the hand.pop(all(hand)) method. Because what it really does is popping the second element of the non-empty array.

Because all(hand) always returns True and hand.pop(True) is being cast to hand.pop(1) and it removes the element at position 1 from the array.

That's the reason the element in position '0' is never touched - because you never remove it.