Save a numpy matrix

Question

I have a 3D array and I would like to obtain a 2D image along X-Y with the maximum value of z at each point and save it as a numpy array.

import numpy as num
matrix=num.load('3d')
nx,ny,nz=num.shape(matrix)
CXY=num.zeros([ny, nx])
    for i in range(ny):
        for j in range(nx):
            CXY[i,j]=num.max(matrix[j,i,:])

The problem is to save the obtained matrix. I would like to save it with numpy.save but I always get an empty array. Does anyone have suggestions to properly save the obtained array?

I just used num.save:

num.save('max', CXY[i,j])

Answer 1

I guess that you're looking for the numpy.savetxt which saves in a human readable format instead of the numpy.save which saves as a binary format.

import numpy as np
matrix=np.random.random((10,10,42))
nx,ny,nz=np.shape(matrix)
CXY=np.zeros([ny, nx])
for i in range(ny):
    for j in range(nx):
        CXY[i,j]=np.max(matrix[j,i,:])

#Binary data
np.save('maximums.npy', CXY)

#Human readable data
np.savetxt('maximums.txt', CXY)

This code saves the array first as a binary file and then as a file you can open in a regular text editor.