python - Pandas - 无法让 Series.isin 工作

Question

我有一个比赛结果的数据框，我想看看比赛的获胜者是否来自与比赛相同的地点。

round_loc 列:

0                       Val d'Allos, France
168                  Les Deux Alpes, France
378                    Winter Park, CO, USA
499                    Whistler, BC, Canada
...

国家栏:

0              France
168            France
378            France
499         Australia
602            France
...

我的代码:

winners_df = df.loc[df['finish_position'] == 1, ['country', 'round_loc']]
hometown_win = winners_df['country'].isin(winners_df['round_loc'])

# Also tried

hometown_win = winners_df['country'].isin(winners_df['round_loc'].values)

print(hometown_win)

我的结果:

0       False
168     False
378     False
499     False
602     False
...

不知道我做错了什么。

winners_df['country'][0] in winners_df['round_loc'][0]

工作正常。我确信我可以用循环来完成它，但我觉得我在这里遗漏了一些东西。

Answer 1

print (winners_df)
                  round_loc    country
0       Val d'Allos, France     France
168  Les Deux Alpes, France        USA <-changed data sample
378    Winter Park, CO, USA     France
499    Whistler, BC, Canada  Australia

如果需要检查round_loc列中是否是country列中的一个值:

a = '|'.join(winners_df['country'].unique().tolist())
print (a)
France|USA|Australia

hometown_win = winners_df['round_loc'].str.contains(a)
print(hometown_win)
0       True
168     True
378     True
499    False
Name: round_loc, dtype: bool

如果需要检查round_loc列中是否是country列中的一个值，但每行:

hometown_win = winners_df.apply(lambda x: x['country'] in x['round_loc'],axis=1)
print(hometown_win)
0       True
168    False
378    False
499    False
dtype: bool