Declare an empty array in Python

Hello friends, in this tutorial I will tell you how you can initialize an empty array in Python.

I will cover three ways of doing so :

• Initialization using Python
• Initialization using Numpy
• Initialization using itertools 

Initialize an empty array in Python

1.  Initialize using Python

In this example, I have taken a temporary variable, arr. This variable holds a list of 20 zeroes, you can change the number to your likeliness.

Code :

arr = [0] * 20

Output : 

[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

2. Initialize using Numpy

To use the Numpy library, you must install it and import it into your code. You can check out our tutorial on Array creation in Numpy . I have used the empty() function. It takes a number as input which defines the length of the empty array. The other attribute is dtype, which I have defined as an object.

Code :

import numpy
num = 10
arr = numpy.empty(num, dtype = object)

Output : 

[None None None None None None None None None None]

3. Intialize using itertools

itertools is a Python built-in library. After importing the library, I have used the repeat() function that enables an iterator to do a single job a number of times. In this example, I have given 0 and 10 as arguments for the repeat() function because I want to repeat 0, 10 times. I have also typecasted the iterator.repeat() function as a list to return an empty array.

Code :

import itertools
arr = list(itertools.repeat(0, 10))

Output : 

[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

Thus you can now declare an empty array in Python.