CODEWITHSUNDEEP
pythonlistdataframe
amarokWPcom
amarokWPcom

Reputation: 81

Python: Create List from table

I think the solution is very simple but I don't have any idea why I am so stupid today....

I have a dataframe like this

A B C
1 a red
1 a blue
1 c blue
1 c yellow
2 b red
2 d blue
3 a green
3 c yellow 
3 d blue
3 d yellow 
3 f red

And the result should be simple like this only a list or one column. So the former 1st column should be the headline with a line break before.

1
a [red, blue]
c [blue, yellow]

2
b [red]
d [blue]

3
a [green]
c [yellow]
d [blue, yellow]
f [red]

Upvotes: 0

Views: 820

Answers (1)

Flursch
Flursch

Reputation: 483

Let df be your DataFrame you defined above. Use pandas.DataFrame.groupby to create groups/subgroups and loop over them:

groups = df.groupby('A')

for g in groups:
    print(g[0]) # "headline" of the following block 
    subgroups = g[1].groupby('B')
    for sg in subgroups:
        print(sg[1]['B'].values[0], sg[1]['C'].values)
    print('  ')

This yields:

1
a ['red' 'blue']
c ['blue' 'yellow']
  
2
b ['red']
d ['blue']
  
3
a ['green']
c ['yellow']
d ['blue' 'yellow']
f ['red']

Upvotes: 1

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