import an array in python

Question

How can I import an array to python (numpy.arry) from a file and that way the file must be written if it doesn\'t already exist.

For example, save out a matrix to a

Answer 1

In Python, Storing a bare python list as a numpy.array and then saving it out to file, then loading it back, and converting it back to a list takes some conversion tricks. The confusion is because python lists are not at all the same thing as numpy.arrays:

import numpy as np
foods = ['grape', 'cherry', 'mango']
filename = "./outfile.dat.npy"
np.save(filename, np.array(foods))
z = np.load(filename).tolist()
print("z is: " + str(z))

This prints:

z is: ['grape', 'cherry', 'mango']

Which is stored on disk as the filename: outfile.dat.npy

The important methods here are the tolist() and np.array(...) conversion functions.