Python remove empty lists

Python – Remove empty List from List Example

In this blog, I will show you how to remove empty list from list using python. We will talk about remove empty list from list in python.

This article will give you example for remove empty list in list using python. first example in using filter() to remove empty list and another example in you can remove all empty lists from a list of lists by using the list comprehension statement [x for x in list if x != []] to filter the list.

Here i will give you two example for python remove empty list from list example. So let’s see the bellow example:

Example 1 : Using filter()

#Python Remove empty List from List using filter()

# Initializing list

myList = [1, [], 2, 3, [], 4, 5, [], [], 9]

# printing original list

print(«The original list is : » + str(myList))

# Remove empty List from List

result = list(filter(None, myList))

# printing result

print («List after empty list removal : » + str(result))

The original list is : [1, [], 2, 3, [], 4, 5, [], [], 9]

List after empty list removal : [1, 2, 3, 4, 5, 9]

# Python Remove empty List from List

# using list comprehension

# Initializing list

myList = [1, [], 2, 3, [], 4, 5, [], [], 9]

# printing original list

print(«The original list is : » + str(myList))

# Remove empty List from List

result = [ele for ele in myList if ele != []]

print («List after empty list removal : » + str(result))

The original list is : [1, [], 2, 3, [], 4, 5, [], [], 9]

List after empty list removal : [1, 2, 3, 4, 5, 9]

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How to Remove Empty Lists from a List of Lists in Python?

In the following, you’ll learn about the two methods using list comprehension and the filter() function to remove all empty lists from a list of lists.

But before that, feel free to play with the code yourself:

Method 1: List Comprehension

How can you remove all empty lists from a list of lists? Say, you’ve got a list of lists

and you want all empty lists removed to obtain the list of lists

Solution: Use list comprehension [x for x in list if x] to filter the list and remove all lists that are empty.

lst = [[1, 2, 3], [1, 2], [], [], [], [1, 2, 3, 4], [], []] print([x for x in lst if x]) # [[1, 2, 3], [1, 2], [1, 2, 3, 4]]

The condition if x evaluates to False only if the list x is empty. In all other cases, it evaluates to True and the element is included in the new list.

You can visualize the execution flow here by clicking the “Next” button:

Method 2: filter()

An alternative is to use the filter() function to remove all empty lists from a list of lists:

lst = [[1, 2, 3], [1, 2], [], [], [], [1, 2, 3, 4], [], []] print(list(filter(lambda x: x, lst)))

The filter() function takes two arguments:

• the filter decision function to check for each element whether it should be included in the filtered iterable (it returns a Boolean value), and
• the iterable to be filtered.

As filter decision function, you use the identity function that just passes the list through. Why does this work? Because only an empty list will be evaluated to False . All other lists will be evaluated to True (and, thus, pass the filtering test).

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Python: Remove empty lists from a given list of lists

Write a Python program to remove empty lists from a given list of lists.

Sample Solution:

Python Code:

list1 = [[], [], [], 'Red', 'Green', [1,2], 'Blue', [], []] print("Original list:") print(list1) print("\nAfter deleting the empty lists from the said lists of lists") list2 = [x for x in list1 if x] print(list2) 

Original list: [[], [], [], 'Red', 'Green', [1, 2], 'Blue', [], []] After deleting the empty lists from the said lists of lists ['Red', 'Green', [1, 2], 'Blue']

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Python remove empty elements from list | Example code

The easiest way is list comprehension to remove empty elements from a list in Python. And another way is to use the filter() method. The empty string «» contains no characters and empty elements could be None or [ ], etc.

Python remove empty elements from a list Example

Using list comprehension

Simp;e iterate through the list and add the non-empty elements.

list1 = ['A', ' ', ' ', 'B', ' ', 'C'] res = [ele for ele in list1 if ele.strip()] print(res) list2 = [1, 6, [], 3, [], [], 9] res = [ele for ele in list2 if ele != []] print(res) 

Using filter() method

Just filter out the None and empty element form list.

If None is used as the first argument to filter() , it filters out every value in the given list, which is False in a boolean context. This includes empty lists.

list2 = [1, 6, [], 3, [], [], 9] res = list(filter(None, list2)) print(res) 

Output: [1, 6, 3, 9]

Use a for loop to remove empty strings from a list

Iterate through the list and check if each string is not an empty string. If it is not an empty string, then add each non-empty string to an initially empty list using the append method.

list1 = ['A', ' ', ' ', 'B', ' ', 'C'] res = [] for i in list1: if i.strip() != '': res.append(i) print(res) list2 = [1, 6, [], 3, [], [], 9] res = [] for i in list2: if i: res.append(i) print(res) 

If you want to get rid of everything that is “falsy”, e.g. empty strings, empty tuples, zeros, you could also use

list2 = [x for x in list1 if x]

Do comment if you have any doubts and suggestions on this Python List topic.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.

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