Convert numpy arry to csv file in python

Question

I want to save the numpy array as a csv file in python

For example given the following array

a = [[1,2,3], [4,5,6], [7,8,9]]

I would like to have a csv file like :

 1   4    7
 2   5    8
 3   6    9

My code bellow gives me the result like :

a.tofile('file1.csv',sep=',')

result:  1 2 3 4 5 6 7 8 9

I have tried the following code as well

df = pd.DataFrame(a)

df.to_csv("file2.csv", index=None)

which does not give me the desired result again

I would appreciate your comments and suggestion.

Zero · Accepted Answer · 2017-09-10 15:03:19Z

3

You could do pd.DataFrame(a).T.to_csv('file2.csv', index=False, header=None)

In [1210]: print pd.DataFrame(a).T.to_csv(index=False, header=None)
1,4,7
2,5,8
3,6,9

answered Sep 10, 2017 at 14:53

Zero

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Comments

RomanPerekhrest · Accepted Answer · 2017-09-10 15:25:51Z

2

Simply with numpy.ndarray.transpose() and numpy.savetxt() routines:

a = np.array([[1,2,3], [4,5,6], [7,8,9]])
np.savetxt('output.csv', a.transpose(), delimiter=',', fmt='%d')

output.csv contents:

1,4,7
2,5,8
3,6,9

answered Sep 10, 2017 at 15:25

RomanPerekhrest

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