如何修复Pandas中生成足球比赛结果条件列的语法错误？

原代码的错误点 #

• Python中不能直接将if-elif-else流程语句赋值给变量，Pandas列操作需要用矢量化函数或apply方法实现批量判断
• 语法错误：elif条件中Football_data_match['goal_scored'<...]缺少闭合方括号]
• 语法错误：Football_data_match['result'] 'lost'缺少赋值运算符=
• 括号不匹配：开头的if(没有正确闭合，且错误地将整个流程语句用括号包裹后赋值

正确代码实现（推荐矢量化方法） #

使用numpy.select处理多条件判断，效率远高于循环或apply，适合大数据集：

import numpy as np
import pandas as pd

# 定义判断条件和对应结果
conditions = [
    Football_data_match['goal_scored'] > Football_data_match['goal_against'],
    Football_data_match['goal_scored'] < Football_data_match['goal_against'],
    Football_data_match['goal_scored'] == Football_data_match['goal_against']
]
choices = ['win', 'lost', 'draw']

# 生成结果列
Football_data_match['result'] = np.select(conditions, choices)

备选方法：嵌套np.where（适合简单三条件）

Football_data_match['result'] = np.where(
    Football_data_match['goal_scored'] > Football_data_match['goal_against'],
    'win',
    np.where(
        Football_data_match['goal_scored'] < Football_data_match['goal_against'],
        'lost',
        'draw'
    )
)

备选方法：apply（不推荐，小数据集可用）

def get_match_result(row):
    if row['goal_scored'] > row['goal_against']:
        return 'win'
    elif row['goal_scored'] < row['goal_against']:
        return 'lost'
    else:
        return 'draw'

Football_data_match['result'] = Football_data_match.apply(get_match_result, axis=1)

内容的提问来源于stack exchange，提问作者Martijn