比较两个不同大小的数据帧的各种（但不是全部）列，并从一个数据帧中仅选择条件为真的那些行

Question

I have two datframes that have different numbers of rows and well as different numbers of columns.

row_List1:

        date   team_home  team_away   goals_home   goals_away   shootout_win   competition

1 2018-06-04 India Kenya 3 0 NaN Friendly 2018
2 2018-06-06 Armenia Moldova 0 0 NaN Friendly 2018
3 2018-06-09 Italy Netherlands 1 1 NaN Friendly 2018

row_List2:

date team_home team_away goals_home goals_away shootout_win competition venue

1 2018-06-04 India Kenya 3 0 NaN Friendly 2018 Home
2 2018-06-05 USA Pakistan 8 5 NaN Friendly 2018 Nuetral
3 2018-06-06 Moldova Armenia 0 0 NaN Friendly 2018 Away
4 2018-06-07 India Srilanka 2 0 NaN Friendly 2018 Home
3 2018-06-09 Italy Netherlands 1 1 NaN Friendly 2018 Away
6 2018-06-04 India Kenya 3 0 NaN Friendly 2018 Home

So row_List2 has more columns and more rows than row_List1.

row_List2 has venues of all matches. I need the to add a column venues in row_List1 and check for a match in row_List1, if it exists in row_List2, I need to extract the venue and add to the new column in row_List1.

I tried the below code:

# row_list1['venue'] = np.where(((row_list1['date'] == row_list2['date']) and (row_list1['team_home'] == row_list2['team_home'] or row_list1['team_home'] == row_list2['team_away']) and (row_list1['team_away'] == row_list2['team_away'] or row_list1['team_away'] == row_list2['team_home']) and (row_list1['goals_home'] == row_list2['goals_home'] or row_list1['goals_home'] == row_list2['goals_away']) and (row_list1['goals_away'] == row_list2['goals_away'] or row_list1['goals_away'] == row_list2['goals_home'])), row_list2['venue'], np.NaN)

These are the conditions I need but the above code gives me an error:

ValueError: Can only compare identically-labeled Series objects

Now one more problem is that the team_home and team_away may be switched in row_List2. So I need to check:

if row_list1['team_home'] == row_list2['team_home'] or row_list1['team_home'] == row_list2['team_away']) and (row_list1['team_away'] == row_list2['team_away'] or row_list1['team_away'] == row_list2['team_home']) and (row_list1['goals_home'] == row_list2['goals_home'] or row_list1['goals_home'] == row_list2['goals_away']) and (row_list1['goals_away'] == row_list2['goals_away'] or row_list1['goals_away'] == row_list2['goals_home'])

What I want as an output is:

row_List1:

        date   team_home  team_away   goals_home   goals_away   shootout_win   competition     venue

1 2018-06-04 India Kenya 3 0 NaN Friendly 2018 Home
2 2018-06-06 Armenia Moldova 0 0 NaN Friendly 2018 Away
3 2018-06-09 Italy Netherlands 1 1 NaN Friendly 2018 Away

Can Anyone please help?

Answer 1

This is kind of hacky but it works. Note that the Armenia-Moldova games don't actually match in your dataframes (they're flipped home/away). I had to .fillna() before performing the comparison because np.nan doesn't == np.nan .

>>> for df in [df1, df2]:
...    df.fillna(0, inplace=True)

>>> df1[[df2.drop('venue', axis=1).eq(r).all(axis=1).any() for r in df1.itertuples(index=False)]]

    date    team_home   team_away   goals_home  goals_away  shootout_win    competition year
0   2018-06-04  India   Kenya   3   0   0.0 Friendly    2018
2   2018-06-09  Italy   Netherlands 1   1   0.0 Friendly    2018

Answer 2

Is this what you are looking for?

df = pd.merge(row_List1,row_List2.drop_duplicates(),how = 'left')

Output:

       date team_home    team_away  goals_home  goals_away  shootout_win  \
0  6/4/2018     India        Kenya           3           0           NaN   
1  6/6/2018   Armenia      Moldova           0           0           NaN   
2  6/9/2018     Italy  Netherlands           1           1           NaN   

  competition  year venue  
0    Friendly  2018  Home  
1    Friendly  2018   NaN  
2    Friendly  2018  Away