How to append to empty array in Numpy?

Posted on By Luke K

Let’s see how to append to an empty array in the Numpy Python module.
numpy reshape array

A little reminder. We already discussed how to create an empty array in Numpy. We used the following code:

import numpy as np

empty_array = np.empty((3, 3))

print(empty_array)

How to append to an empty array?

To append to an empty array, just use the append Numpy function.

import numpy as np

empty_array = np.empty((3, 3))
new_array = np.append(empty_array, 6)

print(new_array)

numpy append empty array python

Using the append method, I’ve added six.

See also  How to create numpy array with zeros?

To append the empty array more and add more values, just use parentheses.

import numpy as np

empty_array = np.empty((3, 3))
new_array = np.append(empty_array, (6, 3))

print(new_array)

numpy append empty array many values python

This is what your array looks like. If you don’t like what you see, you can reshape it now.

import numpy as np

empty_array = np.empty((3, 3))
new_array = np.append(empty_array, (6, 3, 4))
reshape = new_array.reshape(4, 3)

print(reshape)

numpy reshape array

How to append to an empty array from another array?

Going further, you can also append an empty array with the values of another Numpy array. Python code would be like that:

import numpy as np

empty_array = np.empty((3, 3))
values = [1, 2, 3]
new_array = np.append(empty_array, np.array([values]))

print(new_array)

As an output, an empty array has been appended by 1,2,3 values as expected.

[0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 2. 3.]
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