第一次滚动时累积百分比停留在 0.00%

Question

我写了一个代码，给出了 1,000,000 场掷骰子游戏的统计数据。我计算了赢得和输掉的总比赛的百分比，以及 总比赛中输赢的 累计百分比 直到并包括给定的掷骰数 （输出的第 3 列）

问题是它在第一卷时一直给我 0.00%，为什么会这样？

我计算累计百分比的代码：

for i in range(0, len(rolls)):
    p_resolved = rolls[i]*100/craps_game_number
    c_resolved = 100*sum(rolls[0:i])/craps_game_number

    if i!=len(rolls)-1:
        print('{:>5}{:>19.2f}%{:>19.2f}%'.format(i+1,p_resolved,c_resolved))
    else:
        print('{:>5}{:>19.2f}%{:>19.2f}%'.format(i + 1, p_resolved, 100*sum(rolls)/craps_game_number))

如果需要，这里是完整的代码：

import random

def win_or_lose():
    roll = random.randint(1,6)+random.randint(1,6)
    if roll in [7,11]:
        return 'Win',1 # return the outcome and attempts it took to decide
    elif roll in [2,3,12]:
        return 'Loss',1
    else:
        attempts=1
        my_point=roll
        while True:
            roll=random.randint(1,6)+random.randint(1,6)
            attempts+=1 # add 1 until the outcome is decided
            if roll==my_point:
                return 'Win',attempts # return the outcome and rounds
            elif roll==7:
                return 'Loss',attempts # return the outcome and rounds
            else:
                continue

rolls = [0]*25
wins=loss=0
craps_game_number=1000000
for _ in range(craps_game_number):
    outcome,attempts = win_or_lose() # store the outcome and rounds it took to decide
    if outcome=='Win':
        wins+=1
    else:
        loss+=1
    if attempts<=len(rolls):
        rolls[attempts-1]+=1
    else:
        rolls[-1]+=1

print('Percentage of wins: {:.2f}%'.format(wins*100/(craps_game_number)))
print('Percentage of losses: {:.2f}%'.format(loss*100/(craps_game_number)))
print('Percentage of wins/losses based on total number of rolls')
print()
print('{:>25}{:>20} '.format('% Resolved','Cummulative %'))
print('{:<5}{:>20} {:>20}'.format('Rolls','on this roll','of games resolved'))

for i in range(0, len(rolls)):
    p_resolved = rolls[i]*100/craps_game_number
    c_resolved = 100*sum(rolls[0:i])/craps_game_number

    if i!=len(rolls)-1:
        print('{:>5}{:>19.2f}%{:>19.2f}%'.format(i+1,p_resolved,c_resolved))
    else:
        print('{:>5}{:>19.2f}%{:>19.2f}%'.format(i + 1, p_resolved, 100*sum(rolls)/craps_game_number))

Answer 1

如果您更改此行：

c_resolved = 100*sum(rolls[0:i])/craps_game_number

...为此：

c_resolved = 100*sum(rolls[0:i + 1])/craps_game_number

...你应该得到这样的输出，我认为这就是问题所要求的：

               % Resolved       Cummulative %
Rolls        on this roll    of games resolved
    1              33.35%              33.35%
    2              18.80%              52.15%
    3              13.49%              65.64%
    4               9.64%              75.28%
    5               6.91%              82.19%
    6               4.98%              87.16%
    7               3.57%              90.73%
    8               2.58%              93.31%
    9               1.85%              95.16%
   10               1.35%              96.51%
   11               0.97%              97.48%
   12               0.69%              98.17%
   13               0.50%              98.67%
   14               0.36%              99.03%
   15               0.26%              99.29%
   16               0.19%              99.48%
   17               0.14%              99.62%
   18               0.10%              99.72%
   19               0.08%              99.80%
   20               0.05%              99.85%
   21               0.04%              99.89%
   22               0.03%              99.92%
   23               0.02%              99.94%
   24               0.02%              99.96%
   25               0.04%             100.00%

这将使累积结果的第一行成为 non-zero，并且还应更正最后一行之前所有后续行的值（通过 special-case 逻辑将其设置为 100% ).