Remove None From List, List of List and Array In Python (Examples)

Remove None From List

Here are a few ways to remove None values from a list in Python:

Using a List Comprehension

# Example of using a list comprehension to remove None values from a list

my_list = [1, None, 2, None, 3, None, 4]
new_list = [item for item in my_list if item is not None]
print(new_list)

Output:

[1, 2, 3, 4]

Using the filter() Function

# Example of using the filter() function to remove None values from a list

my_list = [1, None, 2, None, 3, None, 4]
new_list = list(filter(lambda x: x is not None, my_list))
print(new_list)

Output:

[1, 2, 3, 4]

Using a for Loop

# Example of using a for loop to remove None values from a list

my_list = [1, None, 2, None, 3, None, 4]
new_list = []
for item in my_list:
    if item is not None:
        new_list.append(item)
print(new_list)

Output:

[1, 2, 3, 4]

Using the list() Constructor

# Example of using the list() constructor to remove None values from a list

my_list = [1, None, 2, None, 3, None, 4]
new_list = list(filter(None, my_list))
print(new_list)

Output:

[1, 2, 3, 4]

Remove None From List of List

Here are ways to remove None values from a list of list:

Using a Nested List Comprehension

# Example of using a nested list comprehension to remove None values from a list of lists

my_list = [[1, None, 2], [None, 3, None], [4, None, None]]
new_list = [[item for item in inner_list if item is not None] for inner_list in my_list]
print(new_list)

Output:

[[1, 2], [3], [4]]

Using a Filter Function with Lambda

# Example of using a filter function with lambda to remove None values from a list of lists

my_list = [[1, None, 2], [None, 3, None], [4, None, None]]
new_list = list(map(lambda x: list(filter(lambda y: y is not None, x)), my_list))
print(new_list)

Output:

[[1, 2], [3], [4]]

Using a List Comprehension with any()

# Example of using a list comprehension with any() to remove None values from a list of lists

my_list = [[1, None, 2], [None, 3, None], [4, None, None]]
new_list = [list(filter(lambda x: x is not None, inner_list)) for inner_list in my_list if any(inner_list)]
print(new_list)

Output:

[[1, 2], [3], [4]]

Remove None From Array

Here are a few ways to remove None values from an array in Python:

Using a List Comprehension

# Example of using a list comprehension to remove None values from an array

import numpy as np

my_array = np.array([1, None, 2, None, 3, None, 4])
new_array = np.array([item for item in my_array if item is not None])
print(new_array)

Output:

[1 2 3 4]

Using the where() Function

# Example of using the where() function to remove None values from an array

import numpy as np

my_array = np.array([1, None, 2, None, 3, None, 4])
new_array = np.where(my_array != None)[0]
print(new_array)

Output:

[0 2 4 6]

Using the delete() Function

# Example of using the delete() function to remove None values from an array

import numpy as np

my_array = np.array([1, None, 2, None, 3, None, 4])
new_array = np.delete(my_array, np.where(my_array == None))
print(new_array)

Output:

[1 2 3 4]