How to export list of arrays to csv in Python?

Question

I have this list in Python:

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

and I would like to export this to csv to look like this: each array on a new line ...

 1, 2, 3 3., 4., 5., 6., 7. 7, 8 

Each array has a different length.

I tried using numpy.savetxt , numpy.vstack , but these different lengths give me problems.

Can anyone help?

Answer 1

You can also use:

 import csv import numpy as np b = open('output.csv', 'w') a = csv.writer(b) data = [np.array([1, 2, 3]), np.array([3., 4., 5., 6., 7.]), np.array([7, 8])] a.writerows(data) b.close() 

Answer 2

Pandas module is especially good for working with data that has no values:

 import pandas as pd arr = [[1, 2, 3], [3, 4], [5, 6, 7, 8]] df = pd.DataFrame(arr) print(df.to_csv(index=False, header=False)) 

Conclusion:

 '1,2,3.0,\n3,4,,\n5,6,7.0,8.0\n'