You can get a list of all matching elements with a list comprehension:
[x for x in myList if x.n == 30] # list of all elements with .n==30
If you simply want to determine if the list contains any element that matches and do it (relatively) efficiently, you can do
def contains(list, filter):
for x in list:
if filter(x):
return True
return False
if contains(myList, lambda x: x.n == 3) # True if any element has .n==3
# do stuff
Top answer 1 of 11
227
You can get a list of all matching elements with a list comprehension:
[x for x in myList if x.n == 30] # list of all elements with .n==30
If you simply want to determine if the list contains any element that matches and do it (relatively) efficiently, you can do
def contains(list, filter):
for x in list:
if filter(x):
return True
return False
if contains(myList, lambda x: x.n == 3) # True if any element has .n==3
# do stuff
2 of 11
106
Simple, Elegant, and Powerful:
A generator expression in conjuction with a builtin… (python 2.5+)
any(x for x in mylist if x.n == 10)
Uses the Python any() builtin, which is defined as follows:
any(iterable)
->Return True if any element of the iterable is true. Equivalent to:
def any(iterable):
for element in iterable:
if element:
return True
return False
Reddit
reddit.com › r/learnpython › python filter a list of class objects by class method using filter built-in function problem
r/learnpython on Reddit: Python filter a list of class objects by class method using Filter built-in function problem
January 21, 2022 -
Like ok... the title said it all. For example : I have a list filled by class name Food. The class uniqueness are defined by name and price attribute. And I create a method to check if the Food is free. the question is how do I use the method to filter the list of Food class using the free checking method of food class?
@dataclass
class Food:
name : str
price : int
def isfree(self):
return self.price == 0
food_list = [Food(name = "curry", price = 5), Food(name = "sushi", price = 0)]
filtered_list = filter(Food.isfree, food_list) # got error TypeError: isfree() takes 0 positional arguments but 2 were given Top answer 1 of 2
1
The code runs fine here: https://i.imgur.com/kXq6AhX.png altough I must add that filter has been superseded by list comprehensions, I would advise to use filtered_list = [f for f in food_list if f.isfree()]
2 of 2
1
Is this really your entire code? What version of python are you using? $ cat test.py from dataclasses import dataclass @dataclass class Food: name : str price : int def isfree(self): return self.price == 0 food_list = [Food(name = "curry", price = 5), Food(name = "sushi", price = 0)] filtered_list = filter(Food.isfree, food_list) print(list(filtered_list)) $ python3 --version Python 3.8.2 $ python3 test.py [Food(name='sushi', price=0)] However it would be more proper to pass a function which would call the proper boundmethod of the instance being passed to the delegated filter function. $cat test.py from dataclasses import dataclass @dataclass class Food: name : str price : int def isfree(self): return self.price == 0 food_list = [Food(name = "curry", price = 5), Food(name = "sushi", price = 0)] filtered_list = filter(lambda food: food.isfree(), food_list) print(list(filtered_list)) $ python3 test.py [Food(name='sushi', price=0)]
Filtering object sets in a Python function
I have an object in my ontology (obj_foo) that i want to filter. I have an array all_ui and want to check if the object property foo_array contains any value in the array all_ui. then, i want to apply all_filters to obj_foo but the filter() method does not exist on the object. here is my current ... More on community.palantir.com
0
0
October 20, 2024Filter list of object with condition in Python - Stack Overflow
But I'd recommend to filter it out upfront before actually appending it to the list, to avoid unnecessary computations due to the need to re-iterate the items i.e. appending only the items that match the criteria. ... for post in get_posts("myhealthkkm", pages=1): if : listposts.append(post) # append the post ... Sign up to request clarification or add additional context in comments. ... A good pythonic ... More on stackoverflow.com
Filtering list of objects on multiple conditions
'm looking for the most straightforward and intuitive way to filter these values. not sure there is an "in-between" where you avoid all the work but also get the functionality.. More on reddit.com
4
1
June 27, 2023Filtering an array of JSON objects by multiple properties
Array.filter is your friend Basically you can do var filterConditionType = "tree"; var filterConditionColors = ["yellow"," brown"]; var arr = *your object* var filteredArray = arr.filter(el=>el.type==filterConditionType&&el.colors.some(e=>filterConditionColors.some(ele=>ele==e))); I think that should work, can't test because I'm on mobile, more on Array.filter https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter More on reddit.com
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40
May 5, 2016Videos
12:13
How Do You Filter A List in Python? 🐍 - YouTube
07:13
How to Use filter() in Python | Filter Data Like a Pro Using Python ...
18:20
Python Filter List - The Easiest Methods - YouTube
Converting a Filter Object to a List in Python
01:53
How to Filter Objects in a List with Unique id Values in Python ...
18:50
MASTERING Python's FILTER Function is Easier Than You Think! - YouTube
Paigeniedringhaus
paigeniedringhaus.com › blog › filter-merge-and-update-python-lists-based-on-object-attributes
Filter, Merge, and Update Python Lists Based on Object Attributes | Paige Niedringhaus
February 23, 2024 - I know this sounds quite complicated, but I broke each of these requirements down into separate methods inside my Python script and learned a lot about working with lists in Python along the way. Today, I’ll show you how to filter lists by whether an attribute exists in an object, how to merge two lists of items together based on matching attributes, and even how to add new object properties to the objects within a list in Python.
GeeksforGeeks
geeksforgeeks.org › python › filter-in-python
filter() in python - GeeksforGeeks
Example: This example shows how to keep only the words starting with the letter 'a' from a list of fruits. ... def starts_a(w): return w.startswith("a") li = ["apple", "banana", "avocado", "cherry", "apricot"] res = filter(starts_a, li) print(list(res)) ... Explanation: function starts_a checks if a word begins with 'a' and filter() applies this function to each fruit and returns only matching ones. ... Return Value: A filter object (an iterator), which can be converted into a list, tuple, set, etc.
Published 5 days ago
Mimo
mimo.org › glossary › python › filter
Python filter(): Syntax, Usage, and Examples
It's particularly useful when working with various data structures in Python. The built-in filter() function creates an iterator from an iterable (like a list) by keeping only the items for which a given function returns True. It provides a clean, functional way to select a subset of data.
Palantir Developer Community
community.palantir.com › ask the community
Filtering object sets in a Python function - Ask the Community - Palantir Developer Community
October 20, 2024 - I have an object in my ontology (obj_foo) that i want to filter. I have an array all_ui and want to check if the object property foo_array contains any value in the array all_ui. then, i want to apply all_filters to obj_foo but the filter() method does not exist on the object. here is my current approach: filter_condition = [obj_foo.foo_array.contains(ui) for ui in all_ui] all_filters = filter_condition[0] for condition in filter_condition[1:]: all_filters |= condition filtered...
DigitalOcean
digitalocean.com › community › tutorials › how-to-use-the-python-filter-function
How To Use the Python Filter Function | DigitalOcean
July 24, 2020 - The filter() function provides a way of filtering values that can often be more efficient than a list comprehension, especially when we’re starting to work with larger data sets. For example, a list comprehension will make a new list, which will increase the run time for that processing.
KDnuggets
kdnuggets.com › 2022 › 11 › 5-ways-filtering-python-lists.html
5 Ways of Filtering Python Lists - KDnuggets
November 14, 2022 - Filter the list elements using for loop, list comprehension, regex, filter(), and lambda functions.
W3Schools
w3schools.com › python › ref_func_filter.asp
Python filter() Function
The filter() function returns an iterator where the items are filtered through a function to test if the item is accepted or not. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: ...
HowToDoInJava
howtodoinjava.com › home › python › python list filter() with examples
Python List filter() with Examples
April 3, 2024 - The filter() function allows us to apply a condition to each element of an iterable (such as a list), retaining only those elements for which the function returns True. The syntax of the filter() function is as follows:
LabEx
labex.io › tutorials › python-how-to-filter-list-by-element-properties-437810
How to filter list by element properties | LabEx
Learn advanced Python list filtering techniques to efficiently filter elements based on specific properties, using list comprehensions, filter() function, and lambda expressions.
DEV Community
dev.to › bybydev › top-3-methods-to-filter-a-list-in-python-19fe
Top 3 methods to filter a list in Python - DEV Community
May 3, 2024 - Python offers versatile list filtering through list comprehensions, filter() function with lambda expressions, or comprehensible conditional statements for concise data manipulation.
Top answer 1 of 5
14
Since you specifically asked about filtering the list you have, you can use filter builtin with lambda to filter out the elements from the list.
>>> list(filter(lambda x: x.get('text', '')=='abc', listpost))
[{'post_id': '01', 'text': 'abc', 'time': datetime.datetime(2021, 8, 5, 15, 53, 19), 'type': 'normal'}]
But I'd recommend to filter it out upfront before actually appending it to the list, to avoid unnecessary computations due to the need to re-iterate the items i.e. appending only the items that match the criteria.
Something like this:
for post in get_posts("myhealthkkm", pages=1):
if <post match the condition>:
listposts.append(post) # append the post
2 of 5
10
simple like that:
filtered_list = [e for e in listpost if e['text'] == 'abc']
GUVI
guvi.in › hub › python › filtering-a-list-using-the-filter()-method-in-python
Filtering a list using the filter() method in Python
With the 'filter()' function, you can selectively extract elements from an iterable, such as a list, based on a defined filtering condition. By specifying a filtering function or lambda expression, the filter() function constructs a new iterable ...
YouTube
youtube.com › the python oracle
Python, Filter a List of Objects, but return a specific attribute? - YouTube
Become part of the top 3% of the developers by applying to Toptal https://topt.al/25cXVn--Music by Eric Matyashttps://www.soundimage.orgTrack title: Puzzle G...
Published January 1, 2023 Views 17
Ceos3c
ceos3c.com › home › python › python filter list – the easiest methods explained
Python Filter List - The Easiest Methods Explained
March 1, 2023 - To Filter a List in Python using a for loop, initiate an empty list and append each item that fits the condition to this empty list. List comprehension is a shorthand version of using a for loop and can be written in one line of code.
Optymize
optymize.io › home › 8 best methods to use python filter list
8 Best Methods To Use Python Filter List | Optymize
March 24, 2023 - Let’s learn about each of them with examples. To filter list of objects, Python has a built-in function- filter() that can be used with lambda. We will learn about the lambda function below.
Technical Feeder
technicalfeeder.com › 2023 › 02 › python-how-to-filter-object-list
Python How to filter object list | Technical Feeder
February 24, 2023 - How can we filter the list in Python then? ... The simplest way is to use for-loop. If the item fulfills the condition, add the item to the result variable. list_1 = [8, 2, 47, 3, 9, 1, 234, 8, 342, 21] list_of_list = [[1, 2, 4], [6, 9, 1], ...
Spark By {Examples}
sparkbyexamples.com › home › python › filter elements from python list
Filter Elements from Python List - Spark By {Examples}
May 31, 2024 - We will iterate all elements and specify some conditions in for loop using if statements within List comprehension to filter elements in Python. If the condition is satisfied, the elements are collected in a List comprehension.
GeeksforGeeks
geeksforgeeks.org › javascript › how-to-filter-object-array-based-on-attributes
How to Filter Object Array based on Attributes? - GeeksforGeeks
July 23, 2025 - The filtered array contains only objects that meet the condition. let newArray = array.filter(function(item) { return conditional_statement; }); Example: We create an array of "students" and call the filter() function on the array to derive ...