How To Convert NumPy Array To List In Python

In this Python NumPy tutorial, we will discuss how to convert numpy array to list in Python.

There are multiple methods to convert numpy array to a list in Python, which is shown below:

Using tolist() function
Using list() constructor
Using a list comprehension
Using the append() method

Table of Contents

Convert NumPy Array to List in Python

There are several ways to convert a NumPy array to a Python list, including using the tolist() method, the list() constructor, a list comprehension, or the append() method.

Each method has its own advantages and disadvantages, and the choice of method depends on the specific requirements of your application.

Method-1: Convert NumPy Array to List using tolist() function

The tolist() method is a built-in method of NumPy arrays that converts a NumPy array to a Python list. This method is very straightforward and efficient and is probably the most common way to convert a NumPy array to a list.

# Import the numpy module
import numpy as np

# Create a one-dimensional numpy array
arr1= np.array([2, 4, 5])

# Convert the numpy array to a python list using the tolist() method
list1 = arr1.tolist()

# Print the resulting python list
print(list1)

The above code first imports the NumPy library with the alias np.

It then creates a one-dimensional NumPy array arr1 containing the values 2, 4, and 5. The tolist() method is then used to convert the NumPy array arr1 to a python list list1.
Finally, the python list list1 is printed to the console using the print() statement.

Method-2: Convert NumPy Array to List using list() constructor

This method uses the built-in list() constructor in Python to convert a NumPy array to a Python list. The list() constructor takes any iterable object as input and returns a new list object containing all the elements of the iterable.

import numpy as np

# Create a NumPy array
arr = np.array(['USA', 'United Kingdom', 'Canada'])

# Convert the NumPy array to a Python list using the list() constructor
lst = list(arr)

# Print the list
print(lst)

The above code creates a NumPy array containing three string values.

It then converts the NumPy array to a Python list using the list() constructor. Finally, it prints the list. This code demonstrates how to convert a NumPy array to a Python list.

Output: ['USA', 'United Kingdom', 'Canada']

Method-3: Convert NumPy Array to List using a list comprehension in Python

This method uses a list comprehension to iterate over the elements of the NumPy array and append them to a new list. A list comprehension is a compact way of creating a new list by iterating over an existing iterable object. This method is simple and efficient.

import numpy as np

# Create a NumPy array
arr = np.array(['USA', 'United Kingdom', 'Canada'])

# Convert the NumPy array to a Python list using a list comprehension
lst_ = [x for x in arr]

# Print the list
print(lst_)

The above code demonstrates how to convert a NumPy array to a Python list using a list comprehension.

First, a NumPy array is created using the np.array() function, which takes a Python list as an argument. The NumPy array contains three string values: ‘USA’, ‘United Kingdom’, and ‘Canada’.
Next, a list comprehension is used to iterate over each element in the NumPy array and append it to a new Python list.
The list comprehension has the syntax [expression for item in iterable], where expression is the operation to be performed on each item, item is the current element in the iterable, and iterable is the object being iterated over.
In this case, the expression is simply the current item x, and the iterable is the NumPy array arr.
Finally, the resulting Python list is printed to the console using the print() function.

Output: ['USA', 'United Kingdom', 'Canada']

Method-4: Convert NumPy Array to List using the append() method

This method uses a for loop to iterate over the elements of the NumPy array and append them to a new list using the append() method provided by Python. T

The append() method is a built-in method in Python that allows you to add elements to the end of a list. This method is simple but less efficient compared to the other methods.

import numpy as np

# Create a NumPy array
arr = np.array(['USA', 'United Kingdom', 'Canada'])

# Convert the NumPy array to a Python list using the append() method
lst = []
for x in arr:
    lst.append(x)

# Print the list
print(lst)

The above code demonstrates how to convert a NumPy array to a Python list using a for loop and the append() method.

First, we create a NumPy array called arr containing the country names ‘USA’, ‘United Kingdom’, and ‘Canada’.
Next, we create an empty list called lst. We then use a for loop to iterate over each element in arr. On each iteration, we append the current element to the lst using the append() method.
Finally, we print the resulting list lst which should contain the same elements as the original NumPy array arr.

Output: ['USA', 'United Kingdom', 'Canada']

In this tutorial, we have covered how to convert numpy array to list in Python using the following methods:

Convert NumPy Array to List using tolist() function
Convert NumPy Array to List using list() constructor
Convert NumPy Array to List using a list comprehension
Convert NumPy Array to List using the append() method