CODEWITHSUNDEEP
pythonpandas
1TonDan
1TonDan

Reputation: 95

Convert a Pandas DataFrame into a list

How do I go from a data frame:

df = pd.DataFrame({'a': range(0, 10), 'b': range(10, 20), 'c': range(20, 30)})

that looks like:

   a   b   c
0  0  10  20
1  1  11  21
2  2  12  22
3  3  13  23
4  4  14  24
5  5  15  25
6  6  16  26
7  7  17  27
8  8  18  28
9  9  19  29

and convert it into a list: ['0','1','2','3','4','5','6','7','8','9','10','11','12','13','14','15','16','17','18','19','20','21','22','23','24','25','26','27','28','29']

Upvotes: 1

Views: 59

Answers (2)

user3212593
user3212593

Reputation: 496

Using numpy:

list(np.reshape(df.values, -1, order='F'))

Your df has a shape of (10,3), and you want a shape of (30,). You can achieve this with numpy's reshape.

-1 is simply a shortcut for (30,) in this instance.

order='F' ensures that you get values "column-wise," as was presented in your desired output.

Using NumPy methods via tolist, you can use:

df.values.reshape(-1, order='F').tolist()

Upvotes: 3

Jack Moody
Jack Moody

Reputation: 1771

I imagine there is probably a better way, but the following will work:

import pandas as pd

df = pd.DataFrame({'a': range(0, 10), 'b': range(10, 20), 'c': range(20, 30)})

mylist = list()
for i in df.columns:
    mylist += map(str, df[i].values.tolist())
print(mylist)

Output:

['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15', '16', '17', '18', '19', '20', '21', '22', '23', '24', '25', '26', '27', '28', '29']

Upvotes: 1

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