Pandas计算电影ROI列时逻辑错误排查求助

我手头有一份电影财务相关的Pandas DataFrame，先给大家看下数据集的基本信息：

<class 'pandas.core.frame.DataFrame'>
RangeIndex: 44691 entries, 0 to 44690
Data columns (total 22 columns):
 #   Column                 Non-Null Count  Dtype
---  ------                 --------------  -----
 0   id                     44691 non-null  int64
 1   title                  44691 non-null  object
 2   tagline                20284 non-null  object
 3   release_date           44657 non-null  datetime64[ns]
 4   genres                 42586 non-null  object
 5   belongs_to_collection  4463 non-null   object
 6   original_language      44681 non-null  object
 7   budget_musd            8854 non-null   float64
 8   revenue_musd           7385 non-null   float64
 9   production_companies   33356 non-null  object
10  production_countries   38835 non-null  object
11  vote_count             44691 non-null  float64
12  vote_average           42077 non-null  float64
13  popularity             44691 non-null  float64
14  runtime                43179 non-null  float64
15  overview               43740 non-null  object
16  spoken_languages       41094 non-null  object
17  poster_path            44467 non-null  object
18  cast                   42502 non-null  object
19  cast_size              44691 non-null  int64
20  crew_size              44691 non-null  int64
21  director               43960 non-null  object
dtypes: datetime64[ns](1), float64(6), int64(3), object(12)
memory usage: 7.5+ MB

我重点关注两个财务字段：

• budget_musd：电影预算（单位：百万美元）
• revenue_musd：电影总票房收入（单位：百万美元）

我想要新增一个ROI列，计算公式是revenue_musd / budget_musd，同时做了空值和零值的判断：如果预算/收入为空，或者其中任意一个为0，就返回0。于是写了下面的函数并应用到DataFrame上：

import pandas as pd

def calculate_roi(row):
    if pd.isna(row['budget_musd']) or pd.isna(row['revenue_musd']):
        return 0
    elif row['budget_musd'] == 0.00 or row['revenue_musd'] == 0.00:
        return 0
    else:
        return row['revenue_musd'] / row['budget_musd']

df['ROI'] = df.apply(lambda row: calculate_roi(row), axis=1)

但现在遇到了逻辑错误：我明明定义了当分母（budget_musd）为0时ROI返回0，但实际结果不对。比如看索引为3965的行（我一开始标注的是行3976，实际是3965）：

id                                                                                                                                                                                        13703
title                                                                                                                                                                            Less Than Zero
tagline                                                                               In Beverly Hills, you can have anything your heart desires. You just can't have it the way it used to be.
release_date                                                                                                                                                                1987-11-06 00:00:00
genres                                                                                                                                                                      Drama|Crime|Romance
belongs_to_collection                                                                                                                                                                       NaN
original_language                                                                                                                                                                            en
budget_musd                                                                                                                                                                                0.00
revenue_musd                                                                                                                                                                              12.40
production_companies                                                                                 Twentieth Century Fox Film Corporation|Amercent Films|American Entertainment Partners L.P.
production_countries                                                                                                                                                   United States of America
vote_count                                                                                                                                                                                77.00
vote_average                                                                                                                                                                               6.10
popularity                                                                                                                                                                                 4.03
runtime                                                                                                                                                                                   98.00
overview                 A college freshman returns to Los Angeles for the holidays at his ex-girlfriend's request, but discovers that his former best friend has an out-of-control drug habit.
spoken_languages                                                                                                                                                        English|Deutsch|Español
poster_path                                                                                   <img src='http://image.tmdb.org/t/p/w185//1GY0ZhAxOR2RgxGnOkeKoKb2mFM.jpg' style='height:100px;'>
cast                                                     Andrew McCarthy|Jami Gertz|Robert Downey Jr.|James Spader|Brad Pitt|Tony Bill|Nicholas Pryor|Michael Bowen|Sarah Buxton|Donna Mitchell
cast_size                                                                                                                                                                                    10
crew_size                                                                                                                                                                                     3
director                                                                                                                                                                        Marek Kanievska
profit                                                                                                                                                                                    12.40
ROI                                                                                                                                                                                12396383.00
Name: 3965, dtype: object

这一行的budget_musd是0.00，按照我的函数逻辑应该返回0，但实际得到的ROI是12396383.00，完全不符合预期。有没有大佬能帮我排查下问题出在哪里？

备注：内容来源于stack exchange，提问作者majid Hakimi