The List in Python is not an Array of fixed-size upon declaration, so it is by design variable in size. Meaning you can just append members into it. Much like ArrayLists in Java!

So if the context of your question(I am just guessing here) is to find ways to limit the size of a particular List in Python, you would have to do it elsewhere, not during declaration.

Useful reference for this topic: https://www.delftstack.com/howto/python/python-initialize-empty-list/

Answer from xhbear on Stack Overflow
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GeeksforGeeks
geeksforgeeks.org › python › declare-an-empty-list-in-python
Declare an Empty List in Python - GeeksforGeeks
July 12, 2025 - We can create an empty list in Python by just placing the sequence inside the square brackets[]. To declare an empty list just assign a variable with square brackets.
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freeCodeCamp
freecodecamp.org › news › python-empty-list-tutorial-how-to-create-an-empty-list-in-python
Python Empty List Tutorial – How to Create an Empty List in Python
June 18, 2020 - You can create an empty list using an empty pair of square brackets [] or the type constructor list(), a built-in function that creates an empty list when no arguments are passed.
Discussions
Why is it common in python to make an empty list or dict first?
In your case it’s completely useless however many times we run a loop and append to a list or add to a variable counter or many such things. This has to exist before we do so. I mean I thought a lot of list comprehension was supposed to help mitigate this very thing lol. for element in some_list: my_list.append(element*2) Will fail. More on reddit.com
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performance - Creating an empty list in Python - Stack Overflow
What is the best way to create a new empty list in Python? l = [] or l = list() I am asking this because of two reasons: Technical reasons, as to which is faster. (creating a class causes overhe... More on stackoverflow.com
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Create an empty list
What have you tried already? Have you learned about for loops and the append method for lists? More on reddit.com
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Can you create a class with an empty list attribute
what should I do to work around this? When you initialize the object, set the attribute to an empty list. More on reddit.com
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Stack Overflow
stackoverflow.com › questions › 72675877 › how-can-i-make-an-empty-list-of-size-4-in-python
How can I make an empty list of size 4 in python? - Stack Overflow
Top answer
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The List in Python is not an Array of fixed-size upon declaration, so it is by design variable in size. Meaning you can just append members into it. Much like ArrayLists in Java!

So if the context of your question(I am just guessing here) is to find ways to limit the size of a particular List in Python, you would have to do it elsewhere, not during declaration.

Useful reference for this topic: https://www.delftstack.com/howto/python/python-initialize-empty-list/

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How can I make an empty list of size 4 in python?

You must not, as these are mutually exclusive requirements: to have list which is empty (i.e. has size 0) and has size 4

python 3.x - Different ways to create an empty list
performance - Creating an empty list in Python
python - Declaring an empty list
Create an empty list with certain size in Python
How can I make multiple empty lists in Python?
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DataCamp
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A Comprehensive Guide to Python Empty Lists | DataCamp
February 2, 2024 - It can be particularly useful when the code's readability and explicitness are prioritized. Here’s an example of it in action: # Create an empty list using the list() function my_empty_list = list()
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Reddit
reddit.com › r/python › why is it common in python to make an empty list or dict first?
r/Python on Reddit: Why is it common in python to make an empty list or dict first?
September 19, 2023 -

Something I've never understood with python is why it is so common for an empty list to be created and then populated with something in a subsequent (or even more common next) line: 

my_list = []
my_list = [i for i in range(1, 21)]

Obviously this is a really really toy example, but I'm consistently finding this in "production" code in multiple places. Is it pythonic? It's basically pure duplication so I doubt it. Is it some hacky "optimisation"? Is it a side effect of the code priorly being a for loop, then turned to a list comprehension but not tidied up right?

I honestly just feel ike I'm missing something key, with the amount of times and variety of places I see this pattern.

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In your case it’s completely useless however many times we run a loop and append to a list or add to a variable counter or many such things. This has to exist before we do so. I mean I thought a lot of list comprehension was supposed to help mitigate this very thing lol. for element in some_list: my_list.append(element*2) Will fail.
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That is not common at all tbh. You might see initialized to empty if you need to append. For example: ‘’’ coros = [] for f in functions: if f.__name__.startswith(“get”) and validate(f): coros.append(f) await asyncio.gather(*coros) ‘’’ Now, you can do that with a list comprehension but it becomes difficult to read, and the result is the same.
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Medium
medium.com › @ryan_forrester_ › how-to-create-empty-lists-in-python-d41cae5267e2
How to Create Empty Lists in Python | by ryan | Medium
October 26, 2024 - # Wrong way - both variables reference ... list1.append(1) print(list2) # Output: [] # list2 is independent · # Less pythonic way empty_list = [] if len(empty_list) == 0: print("List is empty") # More pythonic way if not empty_list: ...
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jdhao's digital space
jdhao.github.io › 2020 › 11 › 22 › python_list_of_empty_list_pitfall
The Correct Way to Create List of Empty List in Python · jdhao's digital space
February 1, 2022 - In each iteration, a new empty list is created. So the 3 sub-list are independent of each other.
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Sentry
sentry.io › sentry answers › python › create a list of a given size in python
Create a list of a given size in Python | Sentry
September 10, 2026 - A more Pythonic way to create the list in the code above would be to use the range function directly in the list creation: ... empty_list = list() # list with zero elements other_empty_list = [] # list with zero elements, alternate syntax short_list ...
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Codemia
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Create an empty list with certain size in Python | Codemia
January 8, 2025 - The fastest way to create a list of a fixed size in Python is multiplication: [None] * n. This allocates the list in a single operation and fills every slot with None (or any other placeholder you choose).
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EDUCBA
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Python Empty List | How to Declare Empty List with Examples
April 13, 2023 - To define an empty list in Python, there are two ways to do this, and they are done either by using square bracket [] or by using a list constructor such as list(). ... Valuation, Hadoop, Excel, Mobile Apps, Web Development & many more.
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Python - Initialize empty array of given length - GeeksforGeeks
09:04
In this example, we are using Python List comprehension for 1D and 2D empty arrays. Using list comprehension like [[0] * 4 for i in range(3)] creates independent lists for each row.
Published: July 12, 2025
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Stack Overflow
stackoverflow.com › questions › 2972212 › creating-an-empty-list-in-python
performance - Creating an empty list in Python - Stack Overflow
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Here is how you can test which piece of code is faster:

Use with AI% python -mtimeit  "l=[]"
10000000 loops, best of 3: 0.0711 usec per loop

% python -mtimeit  "l=list()"
1000000 loops, best of 3: 0.297 usec per loop

However, in practice, this initialization is most likely an extremely small part of your program, so worrying about this is probably wrong-headed.

Readability is very subjective. I prefer [], but some very knowledgable people, like Alex Martelli, prefer list() because it is pronounceable.

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list() is inherently slower than [], because

  1. there is symbol lookup (no way for python to know in advance if you did not just redefine list to be something else!),

  2. there is function invocation,

  3. then it has to check if there was iterable argument passed (so it can create list with elements from it) ps. none in our case but there is "if" check

In most cases the speed difference won't make any practical difference though.

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Purple Engineer
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Python empty list basics and methods explained 🔧📈
December 27, 2025 - This guide is for Python programmers, from beginners learning about data structures to experienced developers seeking best practices. It solves the common challenge of how and when to properly initialize a list to collect data dynamically. You will learn the two standard methods for creating an empty list—using square brackets (`[]`) or the `list()` constructor—and understand the subtle performance differences between them.
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Python Morsels
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Checking for an empty list in Python - Python Morsels
July 18, 2026 - This way, our code would work with an empty list, an empty tuple, or any empty collection. When I write Python code that checks for an empty list, I usually rely on truthiness and falsiness using Python's if statements and the not operator.
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freeCodeCamp
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Python isEmpty() equivalent – How to Check if a List is Empty in Python
April 19, 2023 - Comparing the list to an empty list. The not operator in Python is used for logical negation.
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How to Create Empty List in Python - Spark By {Examples}
May 31, 2024 - How to create an empty list in Python? You can create an empty list by using empty square brackets or using the list() function without any values.
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pydantic.dev › docs › validation › latest › concepts › models
Models | Pydantic Docs
Pydantic relies heavily on the existing Python typing constructs to define models.
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Python - Create an Empty List
May 1, 2025 - You can create an empty list in Python using a pair of square brackets []. This is the most common and straightforward way to initialize an empty list.
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typing — Support for type hints
These objects can be created through special syntax (type parameter lists and the type statement). For compatibility with Python 3.11 and earlier, they can also be created without the dedicated syntax, as documented below.
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Pierian Training
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How to Create and Use an Empty List in Python
April 27, 2023 - Use square brackets [] instead of ‘list()’ constructor while creating an empty list. Avoid using multiple aliases for one mutable type. Be mindful of what kind of copy operations you need (shallow vs deep) when working with complex data structures. By keeping these points in mind while writing your code, it’ll be easier for you spot potential issues before they become problematic later on down the line! The blog post discussed the importance of empty lists in Python programming and provided a step-by-step guide on how to create an empty list.