如何用python模拟原神抽卡

用Python模拟原神抽卡的步骤包括构建池子、设置概率、实现抽卡逻辑、统计结果、优化代码性能。
在详细描述中，我们将展开如何构建池子、设置概率、实现抽卡逻辑，并通过代码实例帮助大家理解。

一、构建池子

原神的抽卡系统分为常驻池和限定池。常驻池包含永久存在的角色和武器，而限定池则会在特定时间段内更新角色和武器。为了模拟抽卡，我们需要定义这些池子。

permanent_pool = {
    "5_star": ["Diluc", "Jean", "Keqing", "Mona", "Qiqi"],
    "4_star": ["Noelle", "Fischl", "Xiangling", "Barbara", "Razor", "Beidou", "Ningguang", "Chongyun", "Bennett"],
    "3_star": ["Cool Steel", "Harbinger of Dawn", "Magic Guide", "Debate Club", "Slingshot", "Sharpshooter's Oath"]
}
limited_pool = {
    "5_star": ["Klee", "Venti", "Childe", "Zhongli"],
    "4_star": ["Sucrose", "Diona", "Xingqiu", "Razor", "Beidou", "Noelle"],
    "3_star": ["Cool Steel", "Harbinger of Dawn", "Magic Guide", "Debate Club", "Slingshot", "Sharpshooter's Oath"]
}

二、设置概率

原神的抽卡机制中，5星角色的基础概率为0.6%，4星角色的基础概率为5.1%，其余为3星武器。我们可以通过设置权重来实现这些概率。

import random
def get_rarity():
    rand = random.random()
    if rand < 0.006:
        return "5_star"
    elif rand < 0.057:
        return "4_star"
    else:
        return "3_star"

三、实现抽卡逻辑

在实现抽卡逻辑时，我们需要考虑保底机制。在原神中，每90次抽卡至少会有一个5星角色，每10次抽卡至少会有一个4星角色。

def draw(pool, pity_5=0, pity_4=0):
    pity_5 += 1
    pity_4 += 1
    if pity_5 >= 90:
        rarity = "5_star"
        pity_5 = 0
    elif pity_4 >= 10:
        rarity = "4_star"
        pity_4 = 0
    else:
        rarity = get_rarity()
        if rarity == "5_star":
            pity_5 = 0
        elif rarity == "4_star":
            pity_4 = 0
    return random.choice(pool[rarity]), pity_5, pity_4

四、统计结果

为了分析模拟的抽卡结果，我们需要统计每次抽卡的结果。

def simulate_draws(pool, num_draws):
    results = {"5_star": 0, "4_star": 0, "3_star": 0}
    pity_5 = 0
    pity_4 = 0
    for _ in range(num_draws):
        rarity, pity_5, pity_4 = draw(pool, pity_5, pity_4)
        results[rarity] += 1
    return results

五、优化代码性能

在实际应用中，为了提升代码性能，我们可以利用NumPy库进行向量化操作，从而加速概率计算和抽卡逻辑。

import numpy as np
def get_rarity_vectorized(size):
    rand = np.random.random(size)
    rarity = np.where(rand < 0.006, "5_star", np.where(rand < 0.057, "4_star", "3_star"))
    return rarity
def draw_vectorized(pool, num_draws):
    pity_5 = np.zeros(num_draws)
    pity_4 = np.zeros(num_draws)
    rarity = get_rarity_vectorized(num_draws)
    for i in range(1, num_draws):
        pity_5[i] = pity_5[i - 1] + 1
        pity_4[i] = pity_4[i - 1] + 1
        if pity_5[i] >= 90:
            rarity[i] = "5_star"
            pity_5[i] = 0
        elif pity_4[i] >= 10:
            rarity[i] = "4_star"
            pity_4[i] = 0
        elif rarity[i] == "5_star":
            pity_5[i] = 0
        elif rarity[i] == "4_star":
            pity_4[i] = 0
    results = {key: np.sum(rarity == key) for key in pool.keys()}
    return results
Example usage
pool = limited_pool
num_draws = 1000
results = draw_vectorized(pool, num_draws)
print(results)