How to save a 3D array in python and Import it in mathematica

Question

I want to save a 3D binary array in .txt file or .csv file on python and import it onto mathematica.

I googled and I found a lot of answers, I try this:

import numpy as np
a=np.zeros((2,3,4))
a[0,0,0]=10
cPickle.dump( a, open( "matrix.txt", "wb" ) )

In mathematica I have used the Import["matrix.txt","Data"] and I did not get what I expect

IN[]:Import["matrix.txt", "Data"]

  Out[]:{{"cnumpy.core.multiarray"}, {"_reconstruct"}, {"p1"}, {"(cnumpy"}, \
    {"ndarray"}, {"p2"}, {"(I0"}, {"tS'b'"}, {"tRp3"}, {"(I1"}, {"(I2"}, \
    {"I3"}, {"I4"}, {"tcnumpy"}, {"dtype"}, {"p4"}, {"(S'f8'"}, {"I0"}, \
    {"I1"}, {"tRp5"}, {"(I3"}, {"S'<'"}, {"NNNI-1"}, {"I-1"}, {"I0"}, \
    {"tbI00"}, \
    {"S'\\x00\\x00\\x00\\x00\\x00\\x00$@\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\\
    x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'"}, {"tb."}}

@OrkunKoçyiğit, I have to get the value of the saved matrix! — Jeanne
– Jeanne, Commented Dec 16, 2015 at 6:25

ogerard · Accepted Answer · 2015-12-17 04:37:48Z

7

The trick is to flatten the array as a 2D-array :

import numpy as np
a=np.zeros((2,3,4))
a[0,0,0]=10
b=a.reshape(1,24)

np.savetxt("/matrix.CSV",b,delimiter=',')

and then convert it in 3D in Mathematica after importing, we can use:

 file=Import["matrix.CSV","Data"]
 matrix=ArrayReshape[file, {2, 3, 4}]

edited Dec 17, 2015 at 4:37

ogerard

7359 silver badges15 bronze badges

answered Dec 16, 2015 at 6:50

Jeanne

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1 Comment

ogerard Over a year ago

Congratulations for answering your own question and thanks for having posted it !

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