To initialize a two-dimensional list in Python, use
t = [ [0]*3 for i in range(3)]
But don't use [[v]*n]*n, it is a trap!
>>> a = [[0]*3]*3
>>> a
[[0, 0, 0], [0, 0, 0], [0, 0, 0]]
>>> a[0][0]=1
>>> a
[[1, 0, 0], [1, 0, 0], [1, 0, 0]]
Matplotlib
matplotlib.org › stable › gallery › color › named_colors.html
List of named colors — Matplotlib 3.10.8 documentation
import math import matplotlib.pyplot as plt import matplotlib.colors as mcolors from matplotlib.patches import Rectangle def plot_colortable(colors, *, ncols=4, sort_colors=True): cell_width = 212 cell_height = 22 swatch_width = 48 margin = 12 # Sort colors by hue, saturation, value and name. if sort_colors is True: names = sorted( colors, key=lambda c: tuple(mcolors.rgb_to_hsv(mcolors.to_rgb(c)))) else: names = list(colors) n = len(names) nrows = math.ceil(n / ncols) width = cell_width * ncols + 2 * margin height = cell_height * nrows + 2 * margin dpi = 72 fig, ax = plt.subplots(figsize=(widt
GeeksforGeeks
geeksforgeeks.org › python › python-using-2d-arrays-lists-the-right-way
Using 2D arrays/lists in Python - GeeksforGeeks
Manually initializing and populating ... a list of size N. ... Explanation: range(N) controls list length. A 2D list represents data in rows and columns....
Published December 20, 2025
How to initialize a two-dimensional array (list of lists, if not using NumPy) in Python? - Stack Overflow
List multiplication makes a shallow copy. When you assign to an index, it does a proper change, but access does not, so when you do a[x][y] = 2, it's accessing, not assigning, for the xth index - only the yth access is actually changed. This page helped me explain with diagrams that are probably better than what I tried explaining in this comment: geeksforgeeks.org/python-using-2d... More on stackoverflow.com
Explain 2D Lists
Lists contain things. Lists are things. Therefore, lists can contain lists. That's literally all there is to it. More on reddit.com
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August 3, 20142D array ( list ) in Python
https://www.reddit.com/r/learnpython/wiki/faq#wiki_why_is_my_list_of_lists_behaving_strangely.3F
More on reddit.com 4
1
March 3, 2018Why are 2D arrays in Python so stupid?
Because they aren't arrays, and aren't designed to be pre-allocated like that. Generally, if you need matrices use Numpy. More on reddit.com
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0
September 5, 2019Videos
04:32
Python 2D lists 📎 - YouTube
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Python 2D collections are easy! ⬜ - YouTube
08:02
2 Dimensional Lists - Python - YouTube
03:05
How Does Append Work With 2d Lists In Python - YouTube
05:46
2D List in Python - YouTube
Python 2D arrays and lists - YouTube
DataCamp
campus.datacamp.com › courses › intro-to-python-for-data-science › chapter-2-python-lists
Python Lists | Python
I just told you that lists can also contain lists themselves. Instead of putting the strings in between the numbers, you can create little sublists for each member of the family. One for liz, one for emma and so on. Now, you can tell Python that these sublists are the elements of another list, that I named fam2: the little lists are wrapped in square brackets and separated with commas.
Top answer 1 of 16
649
To initialize a two-dimensional list in Python, use
t = [ [0]*3 for i in range(3)]
But don't use [[v]*n]*n, it is a trap!
>>> a = [[0]*3]*3
>>> a
[[0, 0, 0], [0, 0, 0], [0, 0, 0]]
>>> a[0][0]=1
>>> a
[[1, 0, 0], [1, 0, 0], [1, 0, 0]]
2 of 16
418
A pattern that often came up in Python was
bar = []
for item in some_iterable:
bar.append(SOME EXPRESSION)
which helped motivate the introduction of list comprehensions, which convert that snippet to
bar = [SOME_EXPRESSION for item in some_iterable]
which is shorter and sometimes clearer. Usually, you get in the habit of recognizing these and often replacing loops with comprehensions.
Your code follows this pattern twice
twod_list = [] \
for i in range (0, 10): \
new = [] \ can be replaced } this too
for j in range (0, 10): } with a list /
new.append(foo) / comprehension /
twod_list.append(new) /
Udemy
udemy.com
Online Courses - Learn Anything, On Your Schedule | Udemy
Udemy is an online learning and teaching marketplace with over 250,000 courses and 80 million students. Learn programming, marketing, data science and more.
Snakify
snakify.org › two-dimensional lists (arrays)
Two-dimensional lists (arrays) - Learn Python 3 - Snakify
For example, that's how you display two-dimensional numerical list on the screen line by line, separating the numbers with spaces: ... a = [[1, 2, 3, 4], [5, 6], [7, 8, 9]] for i in range(len(a)): for j in range(len(a[i])): print(a[i][j], end=' ') print() We have already tried to explain that a for-loop variable in Python can iterate not only over a range(), but generally over all the elements of any sequence.
GitHub
github.com › vinta › awesome-python
GitHub - vinta/awesome-python: An opinionated list of awesome Python frameworks, libraries, software and resources.
2 weeks ago - Arcade - Arcade is a modern Python framework for crafting games with compelling graphics and sound. Cocos2d - A framework for building 2D games, demos, and other graphical/interactive applications.
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Beauty and Joy of Computing
bjc.edc.org › Jan2017 › bjc-r › cur › programming › old-labs › python › 2D_lists.html
2D Lists in Python
All of the previously mentioned list functions still operate on 2D lists: >>> cart[0][2] = "cabbage" >>> cart [ ["kale", "spinach", "cabbage"], ["olives", "tomatoes", "avocado"]] Now that you have some experience with lists in Python, try writing a function that takes a list of lists (2D) and returns all the items of each list concatenated together into one new list as shown below: >>> flatten([["a", "b"],["c", "d", "e"], ["f"]]) ["a", "b", "c", "d", "e", "f"] To test this function enter: python3 PythonLab2.py 2
Reddit
reddit.com › r/learnpython › explain 2d lists
r/learnpython on Reddit: Explain 2D Lists
August 3, 2014 -
Hi redditors!
I'm learning Python and I have to do a project with 2D lists. I'm fairly new to programming and I'm having a hard time understanding the format of a 2D list.
I'm trying to create rows and columns with '.' but I can only print out one row.....can someone help me by giving a simple example on how to do 2D lists, please? Oh, and reddit is my last resource. I have been looking for material I can understand but I'm having trouble :_(
Top answer 1 of 2
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Lists contain things. Lists are things. Therefore, lists can contain lists. That's literally all there is to it.
2 of 2
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It may help you visualize it better if you print every row separately: #make an empty list >>>my_2d_list = [] #add the first row >>>my_2d_list.append([1,2,3]) #add the second row >>>my_2d_list.append([4,5,6]) #add the third row >>>my_2d_list.append([7,8,9]) >>>for row in my_2d_list: >>> print row [1, 2, 3] [4, 5, 6] [7, 8, 9] Instead of adding the rows one by one, you can add them all at once like u/Sackboii did. Adding columns is much harder, since python does not require every row to be the same length. Try to avoid that.
Reddit
reddit.com › r/learnpython › 2d array ( list ) in python
r/learnpython on Reddit: 2D array ( list ) in Python
March 3, 2018 -
Hello, I created a 2D array ( list) in 2 different ways. For some reason I am getting different answers when I run a recursive program using these 2 lists: Which is the correct Python way to do it, I am getting incorrect answers using the first method, although the dimensions of the 2 arrays are absolutely the same
First way:
m = [[None]*(len(denoms))]*(n+1)
Second way:
m = [None] * (n+1)
for row in range(n+1):
m[row] = [None] * len(denoms) Top answer 1 of 3
3
https://www.reddit.com/r/learnpython/wiki/faq#wiki_why_is_my_list_of_lists_behaving_strangely.3F
2 of 3
2
First way will have reference to same list object (which is mutable) for all element in outer list.
So changing one will change other list too. If you are doing after this code, you will see the effect.
Oreate AI
oreateai.com › blog › understanding-2d-arrays-in-python-a-practical-guide › 92540c977547471c93a37af7f7204ada
Understanding 2D Arrays in Python: A Practical Guide - Oreate AI Blog
January 21, 2026 - To define a 2D array in Python using lists (since native multi-dimensional arrays aren't directly supported), we typically employ nested lists.
W3Schools
w3schools.com › python › python_dsa_lists.asp
Python Lists and Arrays
In Python, lists are the built-in data structure that serves as a dynamic array.
CodeHS
codehs.com › tutorial › evelyn › 2d-lists-in-python
Tutorial: 2D Lists in Python | CodeHS
Learn how to create and manipulate 2D lists!
GeeksforGeeks
geeksforgeeks.org › python › appending-to-2d-list-in-python
Appending to 2D List in Python - GeeksforGeeks
July 23, 2025 - A 2D list in Python is a list of lists where each sublist can hold elements. Appending to a 2D list involves adding either a new sublist or elements to an existing sublist.
Csuk
coder.csuk.io › coder_course_page › 2-dimensional-lists
2 Dimensional Lists – CSUK:Coder
A 2D list is essentially a list of lists, allowing you to organise data in rows and columns, much like a table or spreadsheet. In other programming languages, a similar concept is called a 2D array, where data is stored in a grid of rows and columns. In Python, although we don’t have traditional ...
W3Schools
w3schools.com › python › python_lists.asp
Python Lists
List is a collection which is ordered and changeable. Allows duplicate members. Tuple is a collection which is ordered and unchangeable. Allows duplicate members. Set is a collection which is unordered, unchangeable*, and unindexed.
Guru99
guru99.com › home › python › python 2d arrays: two-dimensional list examples
Python 2D Arrays: Two-Dimensional List Examples
August 12, 2024 - We can create a two-dimensional array(list) with rows and columns. ... #creare 2D array with 4 rows and 5 columns array=[[23,45,43,23,45],[45,67,54,32,45],[89,90,87,65,44],[23,45,67,32,10]] #display print(array) #get the first row print(array[0]) #get the third row print(array[2]) #get the first row third element print(array[0][2]) #get the third row forth element print(array[2][3])
Medium
medium.com › @zeebrockeraa › create-and-use-python-2d-list-169e22244ff3
Create And Use Python 2D List
July 8, 2023 - Python 2D list is a very powerful and useful. In this concept, we’ve a Python list and the items of that list are also lists. It looks like a matrix.
Python Pool
pythonpool.com › home › blog › python 2d list: from basic to advance
Python 2d List: From Basic to Advance - Python Pool
January 1, 2024 - The list is one of the most useful data-type in python. We can add values of all types like integers, string, float in a single list. List initialization can be done using square brackets []. Below is an example of a 1d list and 2d list. As we cannot use 1d list in every use case so python 2d list is used.
Processing
py.processing.org › tutorials › 2dlists
Two-Dimensional Lists \ Tutorials
Python Mode for Processing extends the Processing Development Environment with the Python programming language.