Pandas groupby with delimiter join

Question

I tried to use groupby to group rows with multiple values.

col val
A  Cat
A  Tiger
B  Ball
B  Bat

import pandas as pd
df = pd.read_csv(\"Inputfile.txt\", s         


        

Answer 1

Alternatively you can do it this way:

In [48]: df.groupby('col')['val'].agg('-'.join)
Out[48]:
col
A    Cat-Tiger
B     Ball-Bat
Name: val, dtype: object

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UPDATE: answering question from the comment:

In [2]: df
Out[2]:
  col    val
0   A    Cat
1   A  Tiger
2   A  Panda
3   B   Ball
4   B    Bat
5   B  Mouse
6   B    Egg

In [3]: df.groupby('col')['val'].agg('-'.join)
Out[3]:
col
A       Cat-Tiger-Panda
B    Ball-Bat-Mouse-Egg
Name: val, dtype: object

Last for convert index or MultiIndex to columns:

df1 = df.groupby('col')['val'].agg('-'.join).reset_index(name='new')

Answer 2

just try

group = df.groupby(['col'])['val'].apply(lambda x: '-'.join(x))