生成行程全排列DataFrame时Kayak搜索URL生成异常排查

问题根源 #

生成kayak_search_url的代码中，所有航段的起点都固定取了出发城市的IATA码（iata[x['origin']]），没有按照行程逻辑用上一航段的终点作为下一航段的起点，导致后续航段起点始终为AMS，不符合预期。

修复后的完整代码 #

import itertools
import pandas as pd

# 定义行程基础参数
start_city = 'Amsterdam'
end_city = 'Amsterdam'
start_date = '2023-02-14'

cities = ['Warsaw', 'Bogota', 'Milan', 'Santo Domingo']
days = [3,3,3,2]

def generate_permutations(cities, days, start_city, end_city, start_date):
    city_to_days = dict(zip(cities, days))
    
    permutations = list(itertools.permutations(cities))
    df = pd.DataFrame(permutations, columns=['city' + str(i) for i in range(1, len(cities) + 1)])
    df['origin'] = start_city
    df['end'] = end_city
    first_column = df.pop('origin')
    df.insert(0, 'origin', first_column)
    
    st_dt = pd.to_datetime(start_date)
    df = df.assign(flight_dt_1=st_dt)
    
    for i in range(len(cities)):
        df['flight_dt_' + str(i + 2)] = df['flight_dt_' + str(i + 1)] + df['city' + str(i + 1)].map(city_to_days).map(lambda x: pd.Timedelta(days=x))
    
    # IATA城市编码映射
    iata = {'Amsterdam': 'AMS',
            'Warsaw': 'WAW',
            'Bogota': 'BOG',
            'Milan': 'MIL',
            'Santo Domingo': 'SDQ'}

    url = 'https://www.kayak.com/flights/'
    # 修改URL生成逻辑，按行程串联航段
    df['kayak_search_url'] = df.apply(lambda x: url + ''.join(
        # 构建完整行程序列：起点 → 各停留城市 → 终点，配对相邻城市与对应日期
        [f"{iata[prev_city]}-{iata[current_city]},nearby/{date.strftime('%Y-%m-%d')}/"
         for prev_city, current_city, date in zip(
             [x['origin']] + [x[f'city{i+1}'] for i in range(len(cities))],
             [x[f'city{i+1}'] for i in range(len(cities))] + [x['end']],
             [x[f'flight_dt_{i+1}'] for i in range(len(cities)+1)]
         )]
    ) + '?sort=bestflight_a', axis=1)
    
    return df

# 测试调用示例
result_df = generate_permutations(cities, days, start_city, end_city, start_date)
print(result_df['kayak_search_url'].iloc[0])

关键修改说明 #

1. 构建完整行程序列：将起点城市、排列后的各停留城市、终点城市串联成连续列表，确保行程逻辑连贯
2. 配对相邻城市与日期：通过zip同时获取上一城市（航段起点）、当前城市（航段终点）及对应出发日期
3. 动态生成航段URL：每个航段的起点自动继承上一航段的终点，彻底解决固定起点的问题

内容的提问来源于stack exchange，提问作者June Smith