CODEWITHSUNDEEP
pythoncsvdictionary
John Doe
John Doe

Reputation: 364

Write a dict to a csv file on the right order

I have a dict like this :

{
'col1': [1, 2, 3],
'col2': [4, 5, 6],
'col3' : [7, 8, 9]
}

and I want a csv like

col1;col2;col3
1;4;7
2;5;8
3;6;9

I try with for loops but a don't succed to write the values in the right order.

Upvotes: 3

Views: 3237

Answers (3)

deepfish
deepfish

Reputation: 1

If you use pandas, it will be super easy to write to csv file.

import pandas as pd
data = {
    'col1': [1, 2, 3],
    'col2': [4, 5, 6],
    'col3' : [7, 8, 9]
}
df = pd.DataFrame(data, columns=['col1', 'col2', 'col3'])
df.to_csv('csv_file.csv', sep=';', index=False)

Upvotes: 0

Hai Vu
Hai Vu

Reputation: 40763

The key here is to transform

data = {
'col1': [1, 2, 3],
'col2': [4, 5, 6],
'col3' : [7, 8, 9]
}

into a list of rows:

[(1, 4, 7), (2, 5, 8), (3, 6, 9)]

We know that this expression will get a list of columns:

header = ['col1', 'col2', 'col3']
[data[h] for h in header]  # [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

If we zip them together, then we will get what we want:

zip(*(data[h] for h in header))  # [(1, 4, 7), (2, 5, 8), (3, 6, 9)]

With that, we can write the data to the CSV file. Putting it all together:

import csv

data = {
'col1': [1, 2, 3],
'col2': [4, 5, 6],
'col3' : [7, 8, 9]
}

header = ['col1', 'col2', 'col3']
with open('dict_to_csv_in_order.csv', 'wb') as f:
    writer = csv.writer(f)
    writer.writerow(header)
    writer.writerows(zip(*(data[h] for h in header)))

Upvotes: 0

user2390182
user2390182

Reputation: 73480

Sth. like this should work:

import csv

d = {...}
with open('file.csv', 'wb') as f:
    writer = csv.writer(f, delimiter=';')

    header = ['col1', 'col2', 'col3']
    # header = sorted(d.keys()[, key=custom_order_fnc])
    rows = zip(*[d[col] for col in header])

    writer.writerow(header)
    for row in row:
        writer.writerow(row)

Upvotes: 2

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