Удаление пустых элементов списка python
Извините за глупый вопрос, но как удалить пустые элементы из списка в пайтоне?
Для начала стоит формализовать, что такое «пустой» элемент.
«Пустыми» можно считать многие элементы, например,
Если требуется выбросить из коллекции все такие элементы, то можно воспользоваться генератором списка
Или, если список не требуется, генераторным выражением:
Если правило определения «пустого» элемента более сложное, достаточно описать это правило после оператора if в указанных выше выражениях, например,
оставит в списке элементы, которыне не равны списку, содержащему None (важно заметить, что такой список будет пропущен в итоговый набор в первых случаях).
How to remove none from list python (5 Ways)
In this article, we are solving the problem of how to remove none from list python. This type of problem in Python can be solved in many ways, we will be looking in 5 ways to remove none from list in python.
Table of Contents
What is none in python?
None is a keyword in Python used to define a null value or no value at all. It is not the same as an empty string or zero, or false value, it is the data type of the class NoneType in Python.
We can declare none variable as –
Output:-
Why should we remove none from list Python?
When analyzing a large set of data, it is likely that we come across with none values or missing values. To make sure data is clean and tidy for data analysis and data representation removing null values from list data in python is important.
Since null values affect the performance and accuracy of machine learning algorithms it is necessary to handle these none values from data sets before applying the machine learning algorithm. Removing such unwanted null values, and corrupting data before processing the algorithm is called data preprocessing.
Also Read:
- How to remove special characters from string in 4 Ways
- 3 Ways to Convert List to Set
How to remove none from list Python
The 5 Ways to get rid of none in Python are as follows-
Method 1- Remove none from list using filter() method
The easiest way to remove none from list in Python is by using the list filter() method. The list filter() method takes two parameters as function and iterator. To remove none values from the list we provide none as the function to filter() method and the list which contains none values.
None – To eliminate none values we provide none as the function in the filter method
Iterator – An iterator like list, set, or tuple.
Python Code:
Output:-
Method 2- Naive Method
We can also remove none from list in python using a for loop and check whether the values are none if yes ignore it and the rest of the values can be appended to another list.
Python Code:
Output:-
Method 3- Using For loop + list remove()
To remove none from list python we will iterate over the list elements and compare each element with none if we find any none element we will remove none element from the list using the python list remove() method.
The list remove() method takes a single lament as an argument and removes that element from the list.
Python Code:
Output:-
Method 4- Using List Comprehension
To remove none values from list we also use list comprehension. In Python, list comprehension is a way to create a new list from existing other iterables like lists, sets, and tuples. We can also say that list comprehension is a shorter version of for loop. To know about list comprehension you can visit this.
Python Code:
Output:-
Method 5- Using Filter() + lambda function
In python, the lambda function is an anonymous function that is without any name. It takes any number of arguments but can only perform one expression.
As we discuss above filter() method takes a function as input, and since lambda is also one kind of method in python, hence we provide a lambda function and an iterator as input arguments to the filter method.
Python code:
Output:-
Conclusion
Hence we have seen how to remove none from list python in 5 different ways. We can remove none from list python by using filter(), naive method, for loop + remove(), using list comprehension, and filter() + lambda function.
I am Passionate Computer Engineer. Writing articles about programming problems and concepts allows me to follow my passion for programming and helping others.
Удаление пустых элементов списка python
Извините за глупый вопрос, но как удалить пустые элементы из списка в пайтоне?
Ответы (3 шт):
mylist = [x for x in mylist if x]
Вместо последнего x можно написать x is not None , если нули и пустые строки не должны считаться пустыми элементами.
Для начала стоит формализовать, что такое «пустой» элемент.
«Пустыми» можно считать многие элементы, например,
Если требуется выбросить из коллекции все такие элементы, то можно воспользоваться генератором списка
Или, если список не требуется, генераторным выражением:
Если правило определения «пустого» элемента более сложное, достаточно описать это правило после оператора if в указанных выше выражениях, например,
оставит в списке элементы, которыне не равны списку, содержащему None (важно заметить, что такой список будет пропущен в итоговый набор в первых случаях).
Следующий способ будет быстрее (для python 2.7):
а если вы используете python3, то необходимо использовать следующую конструкцию:
How to Use Python to Remove Zeros from List
To remove zeros from a list using Python, the easiest way is to use list comprehension.
You can also use the Python filter() function.
When working with lists of numbers, it can be valuable to be able to easily filter and remove unwanted values from your list.
One such situation where you may want to remove values from a list is if you have a lot of zeros in your list.
We can easily remove all zeros from a list using Python with list comprehension. List comprehension offers a shorter syntax when you want to create a new list based on the values of an existing list.
Below is the code which will allow you to remove all zeros from a list using list comprehension in Python.
Removing Zeros from List with Python filter() Function
The Python filter() function is a built-in function that allows you to process an iterable and extract items that satisfy a given condition.
We can use the Python filter() function to extract all the items in a list of numbers which do not equal 0 and remove the zeros from a list.
Below is some example code showing you how to remove zeros from a list using the filter() function.
Removing Any Value from List Using Python
In a very similar way, we can remove any value from a list using list comprehension.
For example, if we instead wanted to remove all of the ones from a list, we could do that easily with list comprehension in Python by adjusting the code above.
Another example would be if we have a list of strings, and we want to remove the word “whoa”, we can do that with list comprehension in Python.
Hopefully this article has been useful for you to learn how to remove zeros from a list in Python.
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