Python | Remove all strings from a list of tuples

Python – Remove None values from list without removing 0 value

Last Updated : 20 Dec, 2024

Removing None values from a list in Python is a common task when cleaning or processing data. This process helps to filter out unwanted None elements, leaving only the meaningful values in the list for further use. There can be multiple methods to remove None values from a Python list without removing 0.

Using List Comprehension

List comprehension in Python allows us to filter out None values from a list. It’s a fast way to create a new list with only the desired elements.

Example:

Python

a = [1, None, 3, None, 5, 0]

# create a new list `b` that excludes all `None` 
b = [x for x in a if x is not None] 
print(b)

Output

[1, 3, 5, 0]

Explanation:

It filters out None values from list a.
result is stored in list b.

Let’s discuss more method to remove none values from list.

Table of Content

Using filter()
Using itertools.filterfalse()
Using map()
Using del keyword

Using `filter()`

filter() function allows us to remove None values by applying a condition to each element of the list. It creates a new list containing only the elements that meet the specified condition.

Example:

Python

a = [1, None, 3, 0, None, 5]

#remove `None` values from the list
#filter function applies the lambda function to each element of `a`
b = list(filter(lambda x: x is not None, a)) 
print(b)

Output

[1, 3, 5]

Explanation:

filter() with lambda filters out None values from list a.
Result is stored in list b, containing only the non-None elements.

Using itertools.filterfalse()

itertools.filterfalse() filters out None values by applying an inverted condition, keeping only elements that are not None. This approach provides an alternative to filter(), with the same O(n) time complexity for iterating through the list.

Example:

Python

import itertools

# Define a list containing integers and `None` values.
a = [1, None, 3, None, 0 , 5]

#filter out elements that satisfy the condition `x is None`
# lambda function `lambda x: x is None` 
#checks if the element `x` is `None`
b = list(itertools.filterfalse(lambda x: x is None, a))
print(b)

Output

[1, 3, 0, 5]

Explanation:

This code filters out None values from list a.
Result is stored in list b.

Using map()

map() function is applied to each item in the list, which allows for flexible transformations. In this approach, None values are first replaced with None and then removed using a list comprehension, resulting in a clean list.

Example:

Python

a = [1, None, 3, 0, None, 5]

# For `None` elements, the lambda explicitly returns `None`.
b = list(map(lambda x: x if x is not None else None, a)) 
b = [val for val in b if val is not None] 
print(b)

Output

[1, 3, 0, 5]

Explanation:

It applies lambda function to keep or replace None values.
list comprehension removes all None values from the result.

Using del keyword

del keyword allows us to remove None values directly from a list without creating a new one. This method modifies the list in place, making it efficient in terms of memory usage.

Example:

Python

a = [1, None, 3, 0, None, 5]

# Initialize a counter variable `i` to iterate through the list.
i = 0

# Use a `while` loop to iterate over the list.
while i < len(a):
    if a[i] is None:
        del a[i]
    else:
        i += 1
print(a)

Output

[1, 3, 0, 5]

Explanation:

This removes None values from the list a in place.
List is directly modified, keeping only non-None values.

Python | Remove all strings from a list of tuples

manjeet_04

Improve

Article Tags :

Practice Tags :

python

Similar Reads

Python | Remove None values from list

Removing None values from a list in Python is a common task when cleaning or processing data. This process helps to filter out unwanted None elements, leaving only the meaningful values in the list for further use. There can be multiple methods to remove None values from a Python list without removi

Python | Remove all strings from a list of tuples

Given a list of tuples, containing both integer and strings, the task is to remove all strings from list of tuples. Examples: Input : [(1, 'Paras'), (2, 'Jain'), (3, 'GFG'), (4, 'Cyware')] Output : [(1), (2), (3), (4)] Input : [('string', 'Geeks'), (2, 225), (3, '111')] Output : [(), (2, 225), (3,)]

Python - Remove Units from Value List

Sometimes, while working with Python value lists, we can have a problem in which we need to perform removal of units that come along with values. This problem can have direct application in day-day programming and data preprocessing. Let's discuss certain ways in which this task can be performed. In

Python - Remove suffix from string list

To remove a suffix from a list of strings, we identify and exclude elements that end with the specified suffix. This involves checking each string in the list and ensuring it doesn't have the unwanted suffix at the end, resulting in a list with only the desired elements. Using list comprehensionUsin

Python - Remove keys with substring values

Sometimes, we need to remove keys whose values contain a specific substring. For example, consider the dictionary d = {'name1': 'hello world', 'name2': 'python code', 'name3': 'world peace'}. If we want to remove keys where the value contains the substring 'world', the resulting dictionary should ex

Python - Remove String from String List

This particular article is indeed a very useful one for Machine Learning enthusiast as it solves a good problem for them. In Machine Learning we generally encounter this issue of getting a particular string in huge amount of data and handling that sometimes becomes a tedious task. Lets discuss certa

Python - Remove substring list from String

In Python Strings we encounter problems where we need to remove a substring from a string. However, in some cases, we need to handle a list of substrings to be removed, ensuring the string is adjusted accordingly. Using String Replace in a LoopThis method iterates through the list of substrings and

Python - Create a Dictionary using List with None Values

The task of creating a dictionary from a list of keys in Python involves transforming a list of elements into a dictionary where each element becomes a key. Each key is typically assigned a default value, such as None, which can be updated later. For example, if we have a list like ["A", "B", "C"],

Python - Remove digits from Dictionary String Values List

We are given dictionary we need to remove digits from the dictionary string value list. For example, we are given a dictionary that contains strings values d = {'key1': ['abc1', 'def2', 'ghi3'], 'key2': ['xyz4', 'lmn5']} we need to remove digits from dictionary so that resultant output becomes {'key

Python - Remove leading 0 from Strings List

Sometimes, while working with Python, we can have a problem in which we have data which we need to perform processing and then pass the data forward. One way to process is to remove a stray 0 that may get attached to a string while data transfer. Let's discuss certain ways in which this task can be