How To Create Empty Array In Python

Creating empty arrays in Python is a common task that developers encounter. It’s beneficial when you are not sure about the number of elements that will be added to the array, or if you want to initialize the array but not assign any values yet.

In this tutorial, we will discuss different ways to create empty arrays in Python.

Step 1: Using Lists and List Comprehension

The built-in list type is commonly used as an array in Python. To create an empty list, simply use square brackets [] or the list() constructor function:

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empty_list1 = []
empty_list2 = list()

You can also create an empty array with a specific length using list comprehension:

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empty_list_of_length = [None] * 5

This will create a list of length 5, initialized with None values.

Step 2: Using the numpy Library

Another popular option is to use the numpy library, which provides a powerful and efficient n-dimensional array object called numpy.ndarray. To create an empty numpy array, start by installing the numpy library:

pip install numpy

Now, you can use the numpy.empty() function to create an empty array:

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import numpy as np
 
empty_array = np.empty(shape=(0,))

This creates a one-dimensional empty numpy array. You can also create an empty two-dimensional array by specifying the shape as a tuple with two elements:

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empty_2d_array = np.empty(shape=(0, 2))

Step 3: Using the array Module

Python’s array module provides an array type that is more efficient than lists for certain specific use cases. To create an empty array, use the array.array() constructor function:

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import array
 
empty_array = array.array("i", [])

The first argument, "i", specifies the data type of the elements in the array – in this case, integers. Replace it with "f" for floating-point numbers or "d" for double-precision floating-point numbers.

Full Code:

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empty_list1 = []
empty_list2 = list()
 
empty_list_of_length = [None] * 5
 
import numpy as np
 
empty_array = np.empty(shape=(0,))
empty_2d_array = np.empty(shape=(0, 2))
 
import array
 
empty_array = array.array("i", [])

Conclusion

We have discussed three different ways to create empty arrays in Python: using lists and list comprehension, the numpy library, and the array module.

The choice of method depends on your specific use case and the functionality you require. Lists are versatile and easy to use, while numpy arrays and the array module offer greater efficiency and additional functionality for handling numerical data.