List creation from dataframe using for loop

Question

having a dataframe as below:

data={'column1':[1,1,1,1,1,1,1,1,2,2,2,2],'person':['A','A','A','A','B','B','B','B','C','C','C','C'],'location1':['GOA','BANGLORE','GOA','BANGLORE','BANGLORE','DELHI','BANGLORE','DELHII','KOCHI','DELHI','DELHI','KOCHI'],'location2':['BANGLORE','GOA','GOA','BANGLORE','DELHI','DELHI','BANGLORE','BANGLORE','DELHI','KOCHI','DELHI','KOCHI'],'time':[20,40,0,0,34,0,0,23,21,56,0,0]}

df = pd.DataFrame(data)

need to create a list of list

for i in set(df.column1):
    for j in set(df.person):
            col=['location1','location2','time']
            print(df[col].values.tolist())

But couldn't do the rest. Can anyone help me to create list of list?

You shouldn't use an image here. What you have provided in your image can be represented as text formatted as code. You can edit your post to make changes. — Kraigolas
– Kraigolas, Commented Aug 16, 2022 at 14:04
Your code is not valid python. Please make sure your sample code can run first. — Chris
– Chris, Commented Aug 16, 2022 at 14:14
what I mean is that's not a valid dictionary - what is A in that? Shouldn't those be strings? — Chris
– Chris, Commented Aug 16, 2022 at 14:17

score 3 · Accepted Answer · 2022-09-01 10:46:11Z

3

You can start off by grouping the dataframe based on the columns 'column1', person and location1. After that, you use apply to make a list of the results in every group.

grouped_df = df.groupby(['column1','person','location1'])['time'].apply(lambda x:list(x))

column1  person  location1
1        A       BANGLORE     [40, 0]
                 GOA          [20, 0]
         B       BANGLORE     [34, 0]
                 DELHI        [0, 23]
2        C       DELHI        [56, 0]
                 KOCHI        [21, 0]
Name: time, dtype: object

Finally, you perform the same function again.

result = grouped_df.groupby(['column1','person']).apply(lambda x:list(x))

column1  person
1        A         [[40, 0], [20, 0]]
         B         [[34, 0], [0, 23]]
2        C         [[56, 0], [21, 0]]
Name: time, dtype: object

Update

To obtain a dataframe of your desired output, just use reset_index

result.reset_index()

   column1 person                time
0        1      A  [[40, 0], [20, 0]]
1        1      B  [[34, 0], [0, 23]]
2        2      C  [[56, 0], [21, 0]]

edited Sep 1, 2022 at 10:46

answered Aug 16, 2022 at 14:45

user16836078

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6 Comments

Mathew John Over a year ago

i want column1 also on my output.

Mathew John Over a year ago

can you check that too

user16836078 Over a year ago

I have updated it. Is this what you need?

Mathew John Over a year ago

I need the output is in the format as shown in the question. I am trying to create dijikstra algm. I need to prepare the distance matrix. that's what i am trying right now.can you help me? you now i need all the diagonal to zero

user16836078 Over a year ago

I think this is the dataframe you need. For the algm part, this will be a different topic. You can open a new question after you have finished this part :)

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