如何在python中创建产品订单的共现矩阵？

import pandas as pd
from collections import defaultdict

# 假设我们有一个订单数据的DataFrame，包含订单ID和产品ID
data = {
    'order_id': [1, 1, 2, 2, 2, 3, 3],
    'product_id': [101, 102, 101, 103, 104, 102, 103]
}
df = pd.DataFrame(data)

# 获取所有唯一的产品ID
unique_products = df['product_id'].unique()

# 初始化共现矩阵（大小为产品数量x产品数量）
num_products = len(unique_products)
co_occurrence_matrix = [[0] * num_products for _ in range(num_products)]

# 创建产品ID到索引的映射
product_to_index = {product: idx for idx, product in enumerate(unique_products)}

# 遍历每个订单，更新共现矩阵
for order_id, group in df.groupby('order_id'):
    product_ids_in_order = group['product_id'].tolist()
    for i in range(len(product_ids_in_order)):
        for j in range(i + 1, len(product_ids_in_order)):
            idx_i = product_to_index[product_ids_in_order[i]]
            idx_j = product_to_index[product_ids_in_order[j]]
            co_occurrence_matrix[idx_i][idx_j] += 1
            co_occurrence_matrix[idx_j][idx_i] += 1  # 矩阵对称

# 打印共现矩阵
for row in co_occurrence_matrix:
    print(row)