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pythonpandasdataframejoinpandas-groupby
TheObands
TheObands

Reputation: 418

Join rows by specific value in Pandas

I have the following dataframe

     Name     Area
0   Emmeline    G
1       Erek    L
2    Perrine    H
3    Donelle    K
4    Nichols    E
5    Corinne    B
6     Emilia    A
7    Dierdre    G
8    Hadrian    K
9      Tyson    B
10  Emmeline    D
11     Wynne    L
12     Luigi    H
13  Martelle    J
14   Nichols    G
15   Nichols    D
16     Tyson    G
17   Perrine    D
18     Tyson    C
19  Martelle    C

And I want to join rows that have the same name. Thus, the final dataframe must look like

          Name     Area
    0   Emmeline    GD
    1       Erek    L
    2    Perrine    HD
    3    Donelle    K
    4    Nichols    EGD
    5    Corinne    B
    6     Emilia    A
    7    Dierdre    G
    8    Hadrian    K
    9      Tyson    BGC
    10     Wynne    L
    11     Luigi    H
    12  Martelle    JC

I believe I could do this by mixing groupby with join, but I am a little confused on how exactly to do this. Any suggestions?

Upvotes: 1

Views: 152

Answers (3)

Quang Hoang
Quang Hoang

Reputation: 150745

Another option is groupby().apply:

# `as_index` and `sort` options are to match the order in expected output
df.groupby('Name', as_index=False, sort=False)['Area'].apply(''.join)

Output:

        Name Area
0   Emmeline   GD
1       Erek    L
2    Perrine   HD
3    Donelle    K
4    Nichols  EGD
5    Corinne    B
6     Emilia    A
7    Dierdre    G
8    Hadrian    K
9      Tyson  BGC
10     Wynne    L
11     Luigi    H
12  Martelle   JC

Upvotes: 0

sharathnatraj
sharathnatraj

Reputation: 1614

Please try groupby and sum.

df.groupby(by="Name").sum().reset_index()

Upvotes: 4

wwnde
wwnde

Reputation: 26676

Use groupby(), and .str.cat in an agg function

df.groupby('Name')['Area'].agg(lambda x: x.str.cat()).to_frame('Area')



          Area
Name         
Corinne     B
Dierdre     G
Donelle     K
Emilia      A
Emmeline   GD
Erek        L
Hadrian     K
Luigi       H
Martelle   JC
Nichols   EGD
Perrine    HD
Tyson     BGC
Wynne       L

Upvotes: 1

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